JP7762045B2 - Variable magnetic flux magnet module and rotating electric machine - Google Patents

Description

This disclosure relates to a variable magnetic flux magnet module and a rotating electric machine.

Research and development is being conducted into technologies to improve the efficiency of rotating electrical machines.

In this regard, a rotating electric machine is known that includes a rotor and a stator having a variable flux magnet module that includes a variable flux magnet and a magnetizing coil made of a conductor wound around the side of the variable flux magnet (see Non-Patent Document 1). Here, a variable flux magnet is a magnet that can be demagnetized or inmagnetized by applying a magnetic field, and is sometimes referred to as a variable magnet. In this specification, demagnetization means weakening the magnetic force, i.e., reducing the magnetic force. In addition, in this specification, magnetization means strengthening the magnetic force, i.e., increasing the magnetic force. In addition, in this specification, changing the magnetic force is described as transmagnetization.

Y. Yamada and K. Akatsu, "A new motor with stator magnet using the magnetization reversal technique", 2016 XXII International Conference on Electrical Machines (ICEM), Institute of Electrical and Electronics Engineers (IEEE).

When the rotor speed exceeds a predetermined threshold, a rotating electric machine such as that described in Non-Patent Document 1 achieves field weakening by passing current through the magnetizing coils of the variable magnetic flux magnet module included in the rotating electric machine to demagnetize the variable magnetic flux magnets. This improves the efficiency of the rotating electric machine. However, the strength of the magnetic field generated by the magnetizing coil often differs between the center of the magnetizing coil and the outer edge of the magnetizing coil. This difference in magnetic field strength increases individual differences between the variable magnetic flux magnet modules, and as a result, increases individual differences between the rotating electric machine, which is undesirable.

This disclosure was made in consideration of these circumstances, and aims to provide a variable magnetic flux magnet module and rotating electric machine that can reduce individual variations.

One aspect of the present disclosure is a variable flux magnet module comprising a variable flux magnet and one or more coils arranged on at least a first surface of the variable flux magnet.

This disclosure makes it possible to reduce individual differences.

1 is a diagram illustrating an example of the configuration of a rotating electrical machine control system 1. FIG. FIG. 2 is a perspective view showing an example of the configuration of a variable magnetic flux magnet module VMM. FIG. 3 is a perspective view of the variable flux magnet module VMM shown in FIG. 2 as seen from another direction. FIG. 10 is a perspective view showing a first modified example of the configuration of the variable magnetic flux magnet module VMM. FIG. 10 is a perspective view showing a second modified example of the configuration of the variable magnetic flux magnet module VMM. FIG. 10 is a perspective view showing a third modified example of the configuration of the variable magnetic flux magnet module VMM. FIG. 10 is a perspective view showing a fourth modified example of the configuration of the variable magnetic flux magnet module VMM. FIG. 10 is a perspective view showing a fifth modified example of the configuration of the variable magnetic flux magnet module VMM. FIG. 10 is a diagram showing an example of a state in which a variable magnetic flux magnet VM is housed in a recess CC of a magnetic body MB together with 24 magnetizing coils C arranged on a first surface M1. FIG. 10 is a diagram showing an example of a state in which the variable magnetic flux magnet VM is taken out from the recess CC of the magnetic body MB shown in FIG. FIG. 10 is a diagram showing an example of a processing flow in which the control device 20 controls the variable magnetic flux magnet module VMM. FIG. 10 is a diagram showing a first modified example of the flow of processing in which the control device 20 controls the variable magnetic flux magnet module VMM. 10 is a timing chart showing an example of temporal changes in the magnitude of the current that the control device 20 applies to the variable magnetic flux magnet module VMM by repeating the processing of steps S230 to S240. FIG. 10 is a diagram showing a second modified example of the flow of processing in which the control device 20 controls the variable magnetic flux magnet module VMM. 10 is a timing chart showing an example of temporal changes in the magnitude of the current that the control device 20 applies to the variable flux magnet module VMM by repeating the processing of steps S330 to S340. FIG. 10 is a diagram showing a third modified example of the flow of processing in which the control device 20 controls the variable magnetic flux magnet module VMM.

<Embodiment>
Hereinafter, embodiments of the technology according to the present disclosure will be described with reference to the drawings. Herein, a coil in the embodiments refers to a conductor wound around at least one of a certain region and a certain object, and does not include a conductor as a lead wire connecting these conductors to another circuit. However, the coil may also be configured to include a conductor as a lead wire connecting the conductor wound around at least one of a certain region and a certain object to another circuit.

<Configuration of Rotating Electric Machine Control System>
The configuration of the rotating electrical machine control system 1 will be described below with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of the rotating electrical machine control system 1.

The rotating electric machine control system 1 includes a rotating electric machine 10 and a control device 20.

The rotating electric machine 10 is a motor provided to rotate a rotating body in a device that changes the rotation speed of the rotating body in response to a control signal. Examples of such devices include, but are not limited to, motors that drive electric vehicles and motors that drive washing machines.

In the following, as an example, a case will be described in which the rotating electric machine 10 is a three-phase brushless motor. Note that the rotating electric machine 10 may be another type of motor instead of a three-phase brushless motor.

The rotating electric machine 10 includes a rotor 11, a stator 12, and N variable flux magnet modules VMM. To simplify the illustration, FIG. 1 omits components of the rotating electric machine 10 other than the rotor 11 and the stator 12 (e.g., various wiring, Hall sensors, etc.). Here, the N variable flux magnet modules VMM are modules provided on at least one of the rotor 11 and the stator 12. The following describes, as an example, a case in which the N variable flux magnet modules VMM are provided on the rotor 11. Note that instead of being provided on the rotor 11, the N variable flux magnet modules VMM may be provided on the stator 12, or on both the rotor 11 and the stator 12.

The rotor 11 is equipped with N variable flux magnet modules VMM. N may be any integer equal to or greater than 1. In the example shown in FIG. 1, the rotor 11 is equipped with six variable flux magnet modules VMM. In FIG. 1, these six variable flux magnet modules VMM are represented by variable flux magnet module VMM-1 to variable flux magnet module VMM-6, respectively.

The variable flux magnet module VMM is a module that includes a variable flux magnet VM. A variable flux magnet VM is a magnet that can be demagnetized or magnetized by applying a magnetic field. In the rotating electric machine control system 1, field weakening of the rotating electric machine 10 is achieved by demagnetizing the variable flux magnet VM of the variable flux magnet module VMM.

The stator 12 has multiple electromagnets associated with the U, V, and W phases, respectively. In Figure 1, the reference numerals for these multiple electromagnets have been omitted for simplicity's sake.

The control device 20 controls the rotating electric machine 10. In this embodiment, the rotating electric machine 10 is a three-phase brushless motor, as described above. Therefore, the control device 20 rotates the rotating electric machine 10 using PWM (Pulse Width Modulation) control. That is, the control device 20 supplies PWM signals to multiple electromagnets (not shown) provided in the stator 12. Note that the control device 20 may be configured to be controlled by a device higher in level than the control device 20. In this case, the rotating electric machine control system 1 may be configured to include such a higher-level device.

The control device 20 also determines the rotation speed of the rotating electric machine 10 based on, for example, an output signal from a Hall sensor (not shown) provided in the rotating electric machine 10. The control device 20 may be configured to determine the rotation speed using other methods. The method for determining the rotation speed based on the output signal may be a known method or a method to be developed in the future. The control device 20 magnetizes the variable flux magnet VM of the variable flux magnet module VMM provided in the rotating electric machine 10 according to the determined rotation speed. More specifically, the control device 20 changes the magnetic force of the variable flux magnet VM to either a predetermined first magnetic force or a second magnetic force weaker than the first magnetic force according to the determined rotation speed. For example, if the rotation speed is less than a predetermined threshold, the control device 20 sets the magnetic force of the variable flux magnet VM to the first magnetic force. That is, if the rotation speed is less than a predetermined threshold and the magnetic force of the variable flux magnet VM is weaker than the first magnetic force, the control device 20 magnetizes the variable flux magnet VM. Furthermore, if the rotation speed is below a predetermined threshold and the magnetic force of the variable flux magnet VM is the first magnetic force, the control device 20 does not change the magnetic force of the variable flux magnet VM. On the other hand, for example, if the rotation speed is equal to or greater than a predetermined threshold, the control device 20 sets the magnetic force of the variable flux magnet VM to the second magnetic force. That is, if the rotation speed is equal to or greater than a predetermined threshold and the magnetic force of the variable flux magnet VM is stronger than the second magnetic force, the control device 20 demagnetizes the variable flux magnet VM. Furthermore, if the rotation speed is equal to or greater than a predetermined threshold and the magnetic force of the variable flux magnet VM is the second magnetic force, the control device 20 does not change the magnetic force of the variable flux magnet VM. Through this control, the control device 20 can achieve field weakening of the rotating electric machine 10 and improve the efficiency of the rotating electric machine 10. The control device 20 may be configured to discretely change the magnetic force of the variable flux magnet VM in three or more stages depending on the rotation speed.

<Configuration of variable magnetic flux magnet module>
The configuration of the variable magnetic flux magnet module VMM will be described below with reference to Figures 2 and 3. Figure 2 is a perspective view showing an example of the configuration of the variable magnetic flux magnet module VMM. Figure 3 is a perspective view of the variable magnetic flux magnet module VMM shown in Figure 2 when viewed from another direction.

Here, the three-dimensional coordinate system TC is a three-dimensional Cartesian coordinate system that indicates the directions in the drawing in which the three-dimensional coordinate system TC is drawn. Below, for convenience of explanation, the X-axis in the three-dimensional coordinate system TC will be referred to simply as the X-axis. Below, for convenience of explanation, the Y-axis in the three-dimensional coordinate system TC will be referred to simply as the Y-axis. Below, for convenience of explanation, the Z-axis in the three-dimensional coordinate system TC will be referred to simply as the Z-axis.

The variable flux magnet module VMM comprises a variable flux magnet VM and M magnetization coils C.

In the example shown in Figures 2 and 3, the variable flux magnet VM is a variable flux magnet with a flat, rectangular shape. The shape of the variable flux magnet VM may be other than a flat, rectangular shape. The variable flux magnet VM may be composed of multiple variable flux magnet segments, or may be composed of a single variable flux magnet segment. M magnetizing coils C are arranged on the first surface M1 of the surfaces of the variable flux magnet VM. In the example shown in Figures 2 and 3, the first surface M1 is the surface of the variable flux magnet VM facing the positive side of the Z axis. M may be any integer greater than or equal to 1. Below, we will explain the case where M is 24 as an example. Therefore, 24 magnetizing coils C are arranged on the first surface M1 shown in Figure 2. In Figure 2, these 24 magnetizing coils C are each represented by magnetizing coil C-1 to magnetizing coil C-24. In FIG. 2, to avoid cluttering the drawing, reference numerals are omitted for the magnetized coils C-4 to C-23. Below, as an example, a case will be described in which, as shown in FIGS. 2 and 3, 24 magnetized coils C are arranged on the first surface M1 in a matrix of 6 rows and 4 columns, with the rows extending in the X-axis direction and the columns extending in the Y-axis direction. In this case, magnetized coils C-1 to C-4 are arranged in the first row of the first surface M1 in the order of magnetized coil C-1, magnetized coil C-2, magnetized coil C-3, and magnetized coil C-4, facing the positive direction of the X-axis. Furthermore, in this case, magnetized coils C-5 to C-8 are arranged in the second row of the first surface M1 in the order of magnetized coil C-5, magnetized coil C-6, magnetized coil C-7, and magnetized coil C-8, facing the positive direction of the X-axis. In this case, magnetized coils C-9 to C-12 are arranged in the third row of the first surface M1, facing the positive direction of the X-axis, in the order of magnetized coil C-9, magnetized coil C-10, magnetized coil C-11, and magnetized coil C-12. In this case, magnetized coils C-13 to C-16 are arranged in the fourth row of the first surface M1, facing the positive direction of the X-axis, in the order of magnetized coil C-13, magnetized coil C-14, magnetized coil C-15, and magnetized coil C-16. In this case, magnetized coils C-17 to C-20 are arranged in the fifth row of the first surface M1, facing the positive direction of the X-axis, in the order of magnetized coil C-17, magnetized coil C-18, magnetized coil C-19, and magnetized coil C-20. In this case, magnetized coils C-21 to C-24 are arranged in the sixth row of the first surface M1 in the positive direction of the X-axis in the order of magnetized coil C-21, magnetized coil C-22, magnetized coil C-23, and magnetized coil C-24. Note that the arrangement of the 24 magnetized coils C on the first surface M1 may be other than this matrix arrangement. Furthermore, when there is only one magnetized coil C arranged on the first surface M1, the magnetized coil C may be arranged in any position on the first surface M1.

The magnetized coil C may be any coil that is capable of generating a magnetic field that penetrates the first surface M1 when a current is passed through it while it is placed on the first surface M1. In the example shown in Figure 2, the magnetized coil C is a spiral coil with a coil surface that is approximately parallel to the surface on which the magnetized coil C is placed. Here, the coil surface of the magnetized coil C is an imaginary plane with a thickness that includes the conductor wound as the magnetized coil C and the opening that the magnetized coil C has.

When current flows through each of the 24 magnetized coils C arranged on the first surface M1, these 24 magnetized coils C generate a magnetic field that penetrates the first surface M1. In other words, in this case, magnetic flux representing the magnetic field generated by the 24 magnetized coils C penetrates the first surface M1. Below, as an example, we will explain a case where the magnetic force of the variable flux magnet VM increases when the magnetic field penetrates the first surface M1 in the positive direction of the Z axis, and decreases when the magnetic field penetrates the first surface M1 in the negative direction of the Z axis. In this case, when a magnetized coil C generates a magnetic field that penetrates the first surface M1 in the positive direction of the Z axis, the magnetic force of the region of the variable flux magnet VM that overlaps with the coil surface of the magnetized coil C in the Z axis direction changes. As a result, the magnetic force of that region of the variable flux magnet VM increases (i.e., the region is magnetized). On the other hand, when a magnetized coil C generates a magnetic field that penetrates the first surface M1 in the negative direction of the Z axis, the magnetic force of the area of the variable flux magnet VM that overlaps with the magnetized coil C in the Z axis direction changes. As a result, the magnetic force of that area of the variable flux magnet VM decreases (i.e., that area is demagnetized).

Here, a variable flux magnet module X (e.g., a conventional variable flux magnet module, etc.) that is different from the variable flux magnet module VMM has a magnetization coil made up of a conductor wound around the side of the variable flux magnet. As a result, the strength of the magnetic field generated by the magnetization coil often differs between the center of the magnetization coil and the outer edge of the magnetization coil. Such differences in magnetic field strength are undesirable because they increase individual differences between the rotating electric machines.

In contrast, in the variable flux magnet module VMM, each of the 24 magnetized coils C is arranged on the first surface M1 of the variable flux magnet VM. This means that the 24 magnetized coils C are contained within the outline of the first surface M1 in a direction perpendicular to the first surface M1. In other words, in the variable flux magnet module VMM, the area of the coil surface of the magnetized coils C arranged on the first surface M1 can be made smaller than the area of the first surface M1. This situation is independent of the number of magnetized coils C. Therefore, in the variable flux magnet module VMM, for each of the 24 magnetized coils C, the degree of variation in the strength of the magnetic field penetrating the coil surface of the magnetized coil C in the Z-axis direction is smaller than the degree of variation in the strength of the magnetic field penetrating the coil surface of the magnetized coils of the variable flux magnet module X. As a result, the variable flux magnet module VMM can reduce individual variations. This also means that the variable flux magnet module VMM can reduce individual variations in rotating electric machines 10 equipped with the variable flux magnet module VMM. Note that in the variable flux magnet module VMM, some of the 24 magnetized coils C may be configured not to be included inside the outline of the first surface M1 in the direction perpendicular to the first surface M1. Even in this case, the variable flux magnet module VMM reduces the degree of variation in the strength of the magnetic field that penetrates the coil surfaces of the magnetized coils C in the Z-axis direction. As a result, even in this case, the variable flux magnet module VMM can reduce individual variations in the variable flux magnet module VMM and the rotating electric machines 10.

Furthermore, in the variable flux magnet module VMM, the amount of change in the magnetic force of the variable flux magnet VM can be adjusted by changing the number of magnetizing coils C arranged on the first surface M1, the area of the coil surface of each magnetizing coil C arranged on the first surface M1, the number of magnetizing coils C that generate a magnetic field that penetrates the first surface M1 in the positive direction of the Z axis, the number of magnetizing coils C that generate a magnetic field that penetrates the first surface M1 in the negative direction of the Z axis, and the number of magnetizing coils C that do not generate a magnetic field.

It is known that with the variable flux magnet module X described above, even slight differences in the current flowing through the magnetizing coil can cause large changes in the magnetic force of the variable flux magnet. For this reason, it can be difficult to change the magnetic force of the variable flux magnet to the desired magnetic force with the variable flux magnet module X. This means, for example, that field weakening cannot be performed in stages in a rotating electric machine equipped with the variable flux magnet module X, making it difficult to further improve the efficiency of the rotating electric machine.

In contrast, the variable flux magnet module VMM allows the size of each magnetized coil C arranged on the first surface M1 to be adjusted depending on the application. As a result, even if the variable flux magnet module VMM has only one magnetized coil C arranged on the first surface M1, the magnetic force of the variable flux magnet VM can be changed to the desired magnetic force by adjusting the area of the coil surface of the single magnetized coil C arranged on the first surface M1. Naturally, if the variable flux magnet module VMM has two or more magnetized coils C arranged on the first surface M1, it is possible to control and adjust the number of magnetized coils C that generate a magnetic field that penetrates the first surface M1 in the positive direction of the Z axis, the number of magnetized coils C that generate a magnetic field that penetrates the first surface M1 in the negative direction of the Z axis, and the number of magnetized coils C that do not generate a magnetic field. Therefore, in this case, the variable flux magnet module VMM can adjust the amount of change in the magnetic force of the variable flux magnet VM even after manufacture.

In the example shown in Figures 2 and 3, the areas of the coil surfaces of the 24 magnetization coils C are approximately the same. However, the areas of the coil surfaces of some or all of the 24 magnetization coils C may be different from each other.

In the example shown in Figures 2 and 3, each magnetized coil C is in contact with the first surface M1. When each magnetized coil C is in contact with the first surface M1, almost all of the magnetic field generated by each magnetized coil C penetrates the first surface M1. Therefore, when each magnetized coil C is in contact with the first surface M1, the variable flux magnet module VMM can more accurately change the magnetization of the variable flux magnet VM. In other words, in this case, the variable flux magnet module VMM can more reliably reduce individual variations. For example, each magnetized coil C can be positioned on the first surface M1 so as to be in contact with the first surface M1 by fixing it to the first surface M1 with adhesive or the like. Note that some or all of the 24 magnetized coils C may be spaced apart from the first surface M1. In this case, the magnetized coils C that are spaced apart from the first surface M1 are positioned on the first surface M1 using, for example, various jigs or the like.

Furthermore, in the example shown in Figures 2 and 3, the conductors wound as each of the 24 magnetized coils C do not overlap one another. Hereinafter, for ease of explanation, among the regions of the variable magnetic flux magnet VM, the region that overlaps with a certain magnetized coil C in the Z-axis direction (i.e., the region that overlaps with the coil surface of that magnetized coil C) will be referred to as the magnetization change region of that magnetization coil C. In other words, in this example, the magnetization change regions of the 24 magnetization coils C do not overlap. In this case, the magnetic field that penetrates the magnetization change region of a certain magnetization coil C and the magnetic field that penetrates the magnetization change region of another magnetization coil C are unlikely to strengthen or weaken each other. As a result, the variable magnetic flux magnet module VMM can prevent the control of changing the magnetic force of the variable magnetic flux magnet VM from becoming complicated.

Furthermore, as shown in Figures 2 and 3, when the 24 magnetized coils C are adjacent to each other, the variable magnetic flux magnet module VMM can suppress the generation of eddy currents inside the conductors wound as each of the 24 magnetized coils C. In other words, in this case, the variable magnetic flux magnet module VMM can reduce eddy current loss.

<Variation 1 of the configuration of the variable magnetic flux magnet module>
Below, with reference to FIG. 4 , a first modified example of the configuration of the variable magnetic flux magnet module VMM will be described. In this first modified example, the conductors wound as the magnetization coils C for some or all of the 24 magnetization coils C may partially overlap each other. As an example, below, a case will be described in which the conductors wound as the magnetization coils C for all of the 24 magnetization coils C partially overlap each other. FIG. 4 is a perspective view showing a first modified example of the configuration of the variable magnetic flux magnet module VMM. Note that the configuration of the variable magnetic flux magnet module VMM according to this first modified example, other than the configuration in which the conductors wound as the magnetization coils C for all of the 24 magnetization coils C partially overlap each other, is the same as the configuration described in FIGS. 2 and 3 , and therefore description thereof will be omitted.

For example, in FIG. 4, a portion of the conductor wound as magnetizing coil C-1 overlaps with a portion of the conductor wound as magnetizing coil C-2 and a portion of the conductor wound as magnetizing coil C-5. Also, for example, in FIG. 4, a portion of the conductor wound as magnetizing coil C-2 overlaps with a portion of the conductor wound as magnetizing coil C-1, a portion of the conductor wound as magnetizing coil C-3, and a portion of the conductor wound as magnetizing coil C-6. In other words, in FIG. 4, a portion of the conductor wound as each of the 24 magnetizing coils C overlaps with a portion of the conductor wound as an adjacent magnetizing coil C. This allows the variable flux magnet module VMM to increase the size of the magnetization region of each of the 24 magnetization coils C. In other words, the variable flux magnet module VMM can reduce the area of the region of the first surface M1 other than the magnetization region of each of the 24 magnetization coils C.

<Variation 2 of the configuration of the variable magnetic flux magnet module>
Below, a second modified example of the configuration of the variable magnetic flux magnet module VMM will be described with reference to FIG. 5 . In this second modified example, the coil surfaces of some or all of the 24 magnetization coils C may be configured to partially overlap each other. As an example, below, a case will be described in which the coil surfaces of all 24 magnetization coils C partially overlap each other. FIG. 5 is a perspective view showing a second modified example of the configuration of the variable magnetic flux magnet module VMM. Note that the configuration of the variable magnetic flux magnet module VMM according to this second modified example, other than the configuration in which the coil surfaces of the magnetization coils C partially overlap each other for all 24 magnetization coils C, is the same as the configuration described in FIGS. 2 and 3 , and therefore description thereof will be omitted.

For example, in FIG. 5, a portion of the coil surface of magnetized coil C-1 overlaps with a portion of the coil surface of magnetized coil C-2 and a portion of the coil surface of magnetized coil C-5. Also, for example, in FIG. 5, a portion of the coil surface of magnetized coil C-2 overlaps with a portion of the coil surface of magnetized coil C-1, a portion of the coil surface of magnetized coil C-3, and a portion of the coil surface of magnetized coil C-6. That is, in FIG. 5, a portion of the coil surface of each of the 24 magnetized coils C overlaps with a portion of the coil surface of an adjacent magnetized coil C. This allows the variable flux magnet module VMM to increase the size of the magnetization region of each of the 24 magnetized coils C, as long as the individual differences between variable flux magnet modules VMM are not increased. In other words, the variable flux magnet module VMM can reduce the area of the region of the first surface M1 other than the magnetization region of each of the 24 magnetized coils C. Furthermore, the configuration of the variable flux magnet module VMM shown in Figure 5 allows for greater freedom in arranging multiple magnetizing coils C on the first surface M1.

<Variation 3 of the configuration of the variable magnetic flux magnet module>
Below, a third variation of the configuration of the variable flux magnet module VMM will be described with reference to FIG. 6 . In this third variation, a plurality of magnetizing coils C may be arranged on the first surface M1 of the variable flux magnet module VMM so that the white or black regions of a virtual black and white checkerboard pattern arranged on the first surface M1 become magnetized regions. FIG. 6 is a perspective view showing the third variation of the configuration of the variable flux magnet module VMM. In the example shown in FIG. 6 , the variable flux magnet module VMM includes 12 magnetizing coils C instead of 24 magnetizing coils C. Note that the configuration of the variable flux magnet module VMM according to this third variation is the same as the configuration described in FIGS. 2 and 3 , except for the configuration in which a plurality of magnetizing coils C are arranged on the first surface M1 so that the white or black regions of the checkerboard pattern become magnetized regions, and therefore description thereof will be omitted.

<Fourth modified example of variable magnetic flux magnet module configuration>
Below, with reference to FIG. 7 , a fourth modified example of the configuration of the variable flux magnet module VMM will be described. In this fourth modified example, in addition to the first surface M1, one or more magnetizing coils C may be arranged on a second surface M2 different from the first surface M1. Below, as an example, a case will be described in which the second surface M2 is the surface facing the first surface M1, i.e., the surface of the variable flux magnet VM on the negative side of the Z axis. Note that the second surface M2 may be a surface of the variable flux magnet VM other than the first surface M1 and the surface of the variable flux magnet VM on the negative side of the Z axis. FIG. 7 is a perspective view showing the fourth modified example of the configuration of the variable flux magnet module VMM.

The variable magnetic flux magnet VM shown in FIG. 7 has 24 magnetized coils C arranged on the first surface M1, and 24 magnetized coils C arranged on the second surface M2. Here, in this variable magnetic flux magnet VM, two magnetized coils C that overlap in the Z-axis direction are passed through with current so that they generate magnetic fields in the same direction, thereby increasing the amount of change in magnetic force in the magnetized regions of these two magnetized coils C. Note that in this variable magnetic flux magnet VM, the two magnetized coils C that overlap in the Z-axis direction may be composed of a single conductor, or may be composed of separate conductors. Furthermore, the arrangement of one or more magnetized coils C on the second surface M2 may be the same as or different from the 24 magnetized coils C arranged on the first surface M1.

The arrangement of the N magnetizing coils C on the first surface M1 may be a combination of the arrangements shown in each of Figures 3 to 7, or any other arrangement. The arrangement of one or more magnetizing coils C on the second surface M2 may be a combination of the arrangements shown in each of Figures 3 to 7, or any other arrangement.

<Fifth modified example of variable magnetic flux magnet module configuration>
Below, a fifth variation of the configuration of the variable magnetic flux magnet module VMM will be described with reference to Fig. 8. In this fifth variation, the variable magnetic flux magnet module VMM includes a fixed magnet MG in addition to a variable magnetic flux magnet VM and 24 magnetized coils C. Fig. 8 is a perspective view showing the fifth variation of the configuration of the variable magnetic flux magnet module VMM.

The fixed magnet MG can be any permanent magnet whose magnetic force changes little when a magnetic field is applied. In the example shown in Figure 8, the fixed magnet MG is a flat, rectangular magnet. However, the shape of the fixed magnet MG may be other shapes instead of a flat, rectangular shape.

The fixed magnet MG is arranged on the opposite side of the 24 magnetized coils C across the variable flux magnet VM in the direction in which the variable flux magnet VM and the 24 magnetized coils C are stacked. In the example shown in FIG. 8 , the fixed magnet MG is arranged on the opposite side of the 24 magnetized coils C across the variable flux magnet VM in the Z-axis direction so as to overlap with at least a portion of the 24 magnetized coils C. For example, as shown in FIG. 8 , the fixed magnet MG is arranged on the second surface M2 of the variable flux magnet VM. In the example shown in FIG. 8 , the fixed magnet MG is in contact with the variable flux magnet VM. Note that the fixed magnet MG may also be spaced apart from the variable flux magnet VM. In this case, the surface of the fixed magnet MG facing the variable flux magnet VM may be parallel to the second surface M2 of the variable flux magnet VM or may be non-parallel to the second surface M2 of the variable flux magnet VM.

In this way, by including a fixed magnet MG in the variable flux magnet module VMM, the variable flux magnet module VMM can use the combined magnetic force of the variable flux magnet VM and the magnetic force of the fixed magnet MG as the magnetic force of the variable flux magnet module. As a result, the variable flux magnet module VMM can use the fixed magnet MG to adjust the range over which the magnetic force of the variable flux magnet VM can be changed (the range of magnetic force magnitude).

<Variation 6 of the configuration of the variable magnetic flux magnet module>
The following describes a sixth modification of the configuration of the variable flux magnet module VMM. In this sixth modification, the variable flux magnet module VMM includes a magnetic body MB in addition to the variable flux magnet VM and 24 magnetized coils C.

In this embodiment, the magnetic body MB is an unmagnetized magnetic body, such as ferrite. That is, in this embodiment, a distinction is made between an unmagnetized magnetic body and a magnetized magnetic body such as the fixed magnet MG. The magnetic body MB covers at least a portion of the surface of the variable flux magnet VM. The following describes, as an example, a rectangular parallelepiped magnetic body having a recess CC that houses the variable flux magnet VM along with 24 magnetized coils C arranged on the first surface M1. Note that the magnetic body MB may be composed of multiple magnetic body pieces or a single magnetic body piece. Figure 9 is a diagram showing an example of the variable flux magnet VM housed in the recess CC of the magnetic body MB along with 24 magnetized coils C arranged on the first surface M1. Figure 10 is a diagram showing an example of the variable flux magnet VM being removed from the recess CC of the magnetic body MB shown in Figure 9. However, in Figures 9 and 10, to avoid cluttering the diagrams, the 24 magnetization coils C are shown as three magnetization coils C.

As shown in FIG. 9, when the variable magnetic flux magnet VM is covered by the magnetic body MB, almost no (or no) magnetic flux passes through the inside of the conductor wound as the magnetized coil C arranged on the first surface M1. As a result, the variable magnetic flux magnet module VMM can suppress the generation of eddy currents inside the conductor wound as the magnetized coil C arranged on the first surface M1. In other words, in this case, the variable magnetic flux magnet module VMM can reduce eddy current loss.

Note that if the variable flux magnet module VMM further includes a fixed magnet MG, the variable flux magnet VM may be configured to be housed in the recess CC of the magnetic body MB together with the fixed magnet MG, or may be configured to be housed in the magnetic body MB separately from the fixed magnet MG. If the variable flux magnet VM is housed in the magnetic body MB separately from the fixed magnet MG, the magnetic body MB has a recess CC that houses the variable flux magnet VM and a recess that houses the fixed magnet MG.

<Process by which the control device controls the variable flux magnet module>
The process by which the control device 20 controls the variable flux magnet module VMM will be described below with reference to FIG. 11 . FIG. 11 is a diagram showing an example of the flow of the process by which the control device 20 controls the variable flux magnet module VMM. The variable flux magnet module VMM may be configured to include a control unit that executes at least some of the processes of the control device 20 described below. The variable flux magnet module VMM may also be configured integrally with the control device 20. In this case, the control device 20 functions as a control unit for the variable flux magnet module VMM. In this embodiment, the process by which the control device 20 performs PWM control to rotate the rotating electric machine 10 will not be described. The following describes, as an example, a case in which the control device 20 starts rotating the rotating electric machine 10 at a timing before the process of step S110 shown in FIG. 11 is performed. The following describes, as an example, a case in which information indicating the initial value of the magnetic force of the variable flux magnet VM of the variable flux magnet module VMM is stored as magnetic force information in a storage unit (not shown) of the control device 20. The control device 20 repeatedly performs the process of the flowchart shown in FIG. 11, for example, until the rotation of the rotating electrical machine 10 is stopped.

The control device 20 determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S110). Here, in step S110, the control device 20 acquires an output signal at a predetermined sampling period, for example, from a Hall sensor (not shown) provided in the rotating electric machine 10. If the output signal is acquired, the control device 20 determines the rotation speed of the rotating electric machine 10 based on the acquired output signal. The method for determining the rotation speed based on the output signal may be a known method or a method to be developed in the future.

If the control device 20 determines that the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S110-YES), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the second magnetic force (step S120).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the second magnetic force (step S120 - YES), it transitions to step S110 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable flux magnet VM is not the second magnetic force (step S120-NO), it demagnetizes the variable flux magnet VM of the variable flux magnet module VMM (step S130). At this time, the control device 20 passes current through each of the 24 magnetized coils C so that the magnetic flux passes through the magnetized region of each of the 24 magnetized coils C in the negative direction of the Z axis. As a result, the control device 20 demagnetizes the variable flux magnet VM of the variable flux magnet module VMM in step S130. Note that the magnitude of the current passed by the control device 20 to each of the 24 magnetized coils C in step S130 is determined, for example, by prior simulation, theoretical calculations in electromagnetics, repeated trial and error experiments, etc., so that the net magnetic force of the variable flux magnet VM becomes the second magnetic force, but may also be determined by other methods. After the processing of step S130 is performed, the control device 20 updates the magnetic force information stored in the memory unit of the control device 20 to magnetic force information indicating the second magnetic force. The control device 20 then transitions to step S110, where it again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold value.

On the other hand, if the control device 20 determines that the rotation speed of the rotating electric machine 10 is less than the predetermined threshold value (step S110-NO), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the first magnetic force (step S140).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the first magnetic force (step S140 - YES), it transitions to step S110 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable flux magnet VM is not the first magnetic force (step S140-NO), it magnetizes the variable flux magnet VM of the variable flux magnet module VMM (step S150). At this time, the control device 20 passes current through each of the 24 magnetized coils C so that the magnetic flux passes through the magnetized region of each of the 24 magnetized coils C in the positive direction of the Z axis. As a result, the control device 20 magnetizes the variable flux magnet VM of the variable flux magnet module VMM in step S150. Note that the magnitude of the current passed by the control device 20 to each of the 24 magnetized coils C in step S150 is determined, for example, by prior simulation, theoretical calculations in electromagnetics, repeated trial and error experiments, etc., so that the net magnetic force of the variable flux magnet VM is the first magnetic force, but it may also be determined by other methods. After the processing of step S150 is performed, the control device 20 updates the magnetic force information stored in the memory unit of the control device 20 to magnetic force information indicating the first magnetic force. The control device 20 then transitions to step S110, where it again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold value.

As described above, the control device 20 passes current through each of one or more magnetization coils C provided in the variable magnetic flux magnet module VMM in accordance with the rotation speed of the rotating electric machine 10, thereby changing the magnetization of the variable magnetic flux magnet VM. This allows the control device 20 to change the magnetic force of the variable magnetic flux magnet VM to the desired magnetic force. As a result, the control device 20 can achieve highly accurate field weakening of the rotating electric machine 10, improving the efficiency of the rotating electric machine 10.

In step S110, the control device 20 may be configured to compare the rotation speed of the rotating electric machine 10 with two thresholds, a certain threshold A1 and a threshold A2 that is smaller than threshold A1. In this case, if the control device 20 determines that the rotation speed is equal to or greater than threshold A1, it transitions to step S120, and if it determines that the rotation speed is less than threshold A2, it transitions to step S140. This allows the control device 20 to control the variable flux magnet module VMM while taking hysteresis into account.

<Modification 1 of the process in which the control device controls the variable magnetic flux magnet module>
Below, with reference to FIG. 12 , a first modified example of the process in which the control device 20 controls the variable flux magnet module VMM will be described. In this first modified example, the control device 20 passes current through each of the 24 magnetization coils C so that the times at which current flows through each of the 24 magnetization coils C do not overlap. This allows the control device 20 to reduce the maximum value of the current passed through the magnetization coils C when changing the magnetization of the variable flux magnet VM. As a result, the control device 20 can reduce the size of the power supply connected to the control device 20. FIG. 12 is a diagram showing a first modified example of the flow of the process in which the control device 20 controls the variable flux magnet module VMM. Note that the variable flux magnet module VMM may be configured to include a control unit that executes at least some of the processes of the control device 20 described below. Furthermore, the variable flux magnet module VMM may be configured integrally with the control device 20. In this case, the control device 20 functions as a control unit for the variable flux magnet module VMM. The following describes, as an example, a case where the control device 20 starts rotating the rotating electric machine 10 at a timing before the processing of step S210 shown in Fig. 12 is performed. Also, the following describes, as an example, a case where information indicating the initial value of the magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM is stored as magnetic force information in a storage unit (not shown) of the control device 20. The control device 20, for example, repeatedly performs the processing of the flowchart shown in Fig. 12 until the rotation of the rotating electric machine 10 is stopped.

The control device 20 determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S210). The processing of step S210 is the same as the processing of step S110 shown in FIG. 11, and therefore a detailed description thereof will be omitted.

If the control device 20 determines that the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S210 - YES), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the second magnetic force (step S220).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the second magnetic force (step S220 - YES), it transitions to step S210 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is not the second magnetic force (step S220-NO), it selects each of the 24 magnetized coils C provided in the variable magnetic flux magnet module VMM as a target coil, and repeats the process of step S240 for each selected target coil (step S230). Note that the order in which each of the 24 magnetized coils C is selected as a target coil may be random or may be a predetermined order. The predetermined order may be any order.

After the target coil is selected in step S230, the control device 20 passes a current through the selected target coil to demagnetize the target coil's magnetically variable region (step S240). The control device 20 passes a current through the target coil so that the magnetic flux passes through the target coil's magnetically variable region in the negative direction of the Z axis. This causes the control device 20 to demagnetize the target coil's magnetically variable region in step S240. The magnitude of the current passed through the target coil by the control device 20 in step S240 is determined, for example, through prior simulation, theoretical calculations in electromagnetics, or repeated trial-and-error experiments so that the net magnetic force of the variable flux magnet VM becomes the second magnetic force when demagnetization of all the magnetically variable regions of each of the 24 magnetized coils C is complete. However, it may be determined by other methods. After processing in step S240, the control device 20 transitions to step S230 and selects the next target coil. If there is no unselected magnetized coil C that can be selected as the next target coil in step S230, the control device 20 ends the repeated processing of steps S230 to S240. Thereafter, the control device 20 updates the magnetic force information stored in the storage unit of the control device 20 to magnetic force information indicating the second magnetic force. The control device 20 then transitions to step S210, where it again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

In this way, by repeating steps S230 to S240, the control device 20 reduces the magnetic force of the variable flux magnet VM from the first magnetic force to the second magnetic force. In this process, the control device 20 passes current through two or more magnetization coils C so that the time during which current flows through each of the 24 magnetization coils C does not overlap. This allows the control device 20 to reduce the maximum value of the current passed through the magnetization coils C during the magnetization of the variable flux magnet VM. This can be clearly understood by looking at Figure 13. Figure 13 is a timing chart showing an example of the temporal change in the magnitude of the current passed by the control device 20 to the variable flux magnet module VMM by repeating steps S230 to S240. The vertical axis of the graph shown in Figure 13 represents the magnitude of the current. The horizontal axis of the graph represents the elapsed time. For example, in the repeated process of steps S230 to S240 shown in Figure 12, the time during which the control device 20 passes current through each target coil is, for example, 100 microseconds. That is, the width of each pulse on the graph is 100 microseconds. That is, each solid-line pulse on the graph indicates the magnitude of the current flowing through one of the 24 magnetized coils C. In this case, the control device 20 completes the flow of current through all 24 magnetized coils C within 2.4 milliseconds, completing the demagnetization of the variable flux magnet VM. At this time, the control device 20 flows current through two or more magnetized coils C so that the times at which current flows through each of the 24 magnetized coils C do not overlap. Therefore, in the example shown in FIG. 13 , the maximum value of the current that the control device 20 flows through the variable flux magnet module VMM is the magnitude indicated by I1 on the graph. Meanwhile, for example, in step S130 shown in FIG. 11 , the control device 20 flows current through all 24 magnetized coils C during the period from time T1 to time T2. Therefore, in step S130, the maximum value of the current that the control device 20 passes through the variable flux magnet module VMM is indicated by the height of the dotted pulse, and is the magnitude indicated by I2 on the graph. Note that I2 is approximately 24 times I1. In other words, when the control device 20 performs the processing of the flowchart shown in FIG. 12, the control device 20 can reduce the maximum value of the current that passes through the magnetizing coil C when changing the magnetization of the variable flux magnet VM. As a result, in the rotating electric machine control system 1, the power supply connected to the control device 20 can be made smaller.

On the other hand, if the control device 20 determines that the rotation speed of the rotating electric machine 10 is less than the predetermined threshold value (step S210-NO), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the first magnetic force (step S250).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the first magnetic force (step S250 - YES), it transitions to step S210 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is not the first magnetic force (step S250-NO), it selects each of the 24 magnetized coils C provided in the variable magnetic flux magnet module VMM as a target coil, and repeats the process of step S270 for each selected target coil (step S260). Note that the order in which each of the 24 magnetized coils C is selected as a target coil may be random, or may be a predetermined first order. The first order may be any order.

After the target coil is selected in step S260, the control device 20 passes a current through the selected target coil to magnetize the magnetization region of the target coil (step S270). The control device 20 passes a current through the target coil so that magnetic flux passes through the target coil's magnetization region in the positive direction of the Z axis. As a result, the control device 20 magnetizes the target coil's magnetization region in step S270. The magnitude of the current passed through the target coil by the control device 20 in step S270 is determined, for example, through prior simulation, theoretical calculations in electromagnetics, or repeated trial-and-error experiments so that the net magnetic force of the variable flux magnet VM becomes the first magnetic force when the magnetization of all the magnetization regions of each of the 24 magnetized coils C is complete. However, it may be determined by other methods. After processing in step S270, the control device 20 transitions to step S260 and selects the next target coil. If there is no unselected magnetized coil C that can be selected as the next target coil in step S260, the control device 20 ends the repeated processing of steps S260 to S270. Thereafter, the control device 20 updates the magnetic force information stored in the storage unit of the control device 20 to magnetic force information indicating the first magnetic force. The control device 20 then transitions to step S210, where it again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

In this way, by repeating steps S260 to S270, the control device 20 increases the magnetic force of the variable flux magnet VM from the second magnetic force to the first magnetic force. At this time, the control device 20 passes current through each of the 24 magnetized coils C so that the time during which current flows through each of the magnetized coils C does not overlap. This allows the control device 20 to reduce the maximum value of the current passed through the magnetized coils C when changing the magnetization of the variable flux magnet VM. As a result, the rotating electric machine control system 1 allows the power supply connected to the control device 20 to be made smaller.

As described above, the control device 20 passes current through each of the one or more magnetization coils C provided in the variable flux magnet module VMM in accordance with the rotation speed of the rotating electric machine 10, thereby changing the magnetization of the variable flux magnet VM. In this case, the control device 20 passes current through each of the 24 magnetization coils C so that the times at which current flows through each of the 24 magnetization coils C do not overlap. This allows the control device 20 to change the magnetic force of the variable flux magnet VM to the desired magnetic force, while also enabling the power supply connected to the control device 20 to be made smaller.

<Modification 2 of the process in which the control device controls the variable magnetic flux magnet module>
Hereinafter, with reference to FIG. 14 , a second variation of the process in which the control device 20 controls the variable flux magnet module VMM will be described. In this second variation, the 24 magnetized coils C are classified into two or more groups. In this second variation, the control device 20 passes a current through each of the two or more groups so that the times at which the current flows through the two or more groups do not overlap. In this embodiment, when a current is passed through a group among the two or more groups, it means that a current is passed through one or more magnetized coils C classified into that group. By passing a current through the magnetized coils C at different times for each group, the control device 20 can solve problems caused by the arrangement of the 24 magnetized coils C on the first surface M1. Examples of such problems include the magnetic fields of adjacent magnetized coils C canceling each other out and increasing additional vibrations that occur during the rotation of the rotating electric machine 10 due to the magnetization of the variable flux magnet VM. For example, when classifying 24 magnetized coils C into two or more groups, two or more magnetized coils C classified into each group may be arranged so that they are not adjacent to each other. In this case, the control device 20 can prevent overlapping of periods during which current flows through two or more adjacent magnetized coils C among the 24 magnetized coils C. As a result, the control device 20 can prevent magnetic fields of adjacent magnetized coils C from canceling each other out. Furthermore, when classifying 24 magnetized coils C into two or more groups, the 24 magnetized coils C may be classified into two or more groups so that current flows through each magnetized coil C in an order that prevents the additional vibrations generated in the rotation of the rotating electric machine 10 from increasing when the variable magnetic flux magnet VM is magnetized. In this case, the control device 20 can prevent the additional vibrations generated in the rotation of the rotating electric machine 10 from increasing when the variable magnetic flux magnet VM is magnetized. It should be noted that such a classification method is determined, for example, by trial and error in advance experiments.

The following describes, as an example, a case where 24 magnetized coils C are classified into four groups, group G1 to group G4. For example, group G1 contains six magnetized coils C: magnetized coil C-1, magnetized coil C-6, magnetized coil C-11, magnetized coil C-16, magnetized coil C-17, and magnetized coil C-22. For example, group G2 contains six magnetized coils C: magnetized coil C-2, magnetized coil C-7, magnetized coil C-12, magnetized coil C-13, magnetized coil C-18, and magnetized coil C-23. For example, group G3 contains six magnetized coils C: magnetized coil C-3, magnetized coil C-8, magnetized coil C-9, magnetized coil C-14, magnetized coil C-19, and magnetized coil C-24. Furthermore, for example, group G4 is classified into six magnetized coils C: magnetized coil C-4, magnetized coil C-5, magnetized coil C-10, magnetized coil C-15, magnetized coil C-20, and magnetized coil C-21. In this case, the six magnetized coils C in each of these four groups are not adjacent to one another. Therefore, in this case, the control device 20 can change the magnetism of the variable magnetic flux magnet VM while preventing the magnetic fields of adjacent magnetized coils C from canceling each other out.

Figure 14 shows a second variation of the process flow in which the control device 20 controls the variable flux magnet module VMM. The variable flux magnet module VMM may be configured to include a control unit that executes at least some of the processes of the control device 20 described below. The variable flux magnet module VMM may also be configured integrally with the control device 20. In this case, the control device 20 functions as the control unit for the variable flux magnet module VMM. Below, as an example, a case will be described in which the control device 20 starts rotating the rotating electric machine 10 at a timing before the process of step S310 shown in Figure 14 is performed. Below, as an example, a case will be described in which information indicating the initial value of the magnetic force of the variable flux magnet VM of the variable flux magnet module VMM is stored as magnetic force information in a memory unit (not shown) of the control device 20. The control device 20, for example, repeatedly performs the process of the flowchart shown in Figure 14 until the rotation of the rotating electric machine 10 is stopped.

The control device 20 determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S310). The processing of step S310 is the same as the processing of step S110 shown in FIG. 11, and therefore a detailed description thereof will be omitted.

If the control device 20 determines that the rotation speed of the rotating electric machine 10 is equal to or greater than a predetermined threshold (step S310-YES), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the second magnetic force (step S320).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the second magnetic force (step S320 - YES), it transitions to step S310 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is not the second magnetic force (step S320-NO), it selects one of the four groups as a target group and repeats the process of step S340 for each selected target group (step S330). Note that the order in which the four groups are selected one by one as a target group may be random or may be a predetermined order. The predetermined order may be any order.

After the target group is selected in step S330, the control device 20 passes current through the target group and demagnetizes the magnetically variable regions of each of the six magnetized coils C included in the target group (step S340). In this case, the control device 20 passes current through the target coils so that magnetic flux passes through the magnetically variable regions of each of the six magnetized coils C in the negative direction of the Z axis. As a result, the control device 20 demagnetizes the magnetically variable regions of each of the six magnetized coils C in step S340. Note that the magnitude of the current passed by the control device 20 to the target group in step S340 is determined, for example, through prior simulation, theoretical calculations in electromagnetics, repeated trial and error experiments, etc., so that the net magnetic force of the variable flux magnet VM becomes the second magnetic force when demagnetization of all the magnetically variable regions of each of the 24 magnetized coils C is complete. However, it may be determined by other methods. After processing in step S340, the control device 20 transitions to step S330 and selects the next target group. If there is no unselected group that can be selected as the next target group in step S330, the control device 20 ends the repeated processing of steps S330 to S340. The control device 20 then transitions to step S310 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

In this way, by repeating steps S330 to S340, the control device 20 reduces the magnetic force of the variable magnetic flux magnet VM from the first magnetic force to the second magnetic force. At this time, the control device 20 passes current through each of the four groups so that the times at which current flows through the four groups do not overlap. This allows the control device 20 to change the magnetism of the variable magnetic flux magnet VM while preventing the magnetic fields of adjacent magnetized coils C from canceling each other out. In other words, the control device 20 can solve the problems caused by the arrangement of the 24 magnetized coils C on the first surface M1.

FIG. 15 is a timing chart showing an example of the temporal change in the magnitude of the current passed by the control device 20 to the variable flux magnet module VMM as steps S330 to S340 are repeated. The vertical axis of the graph shown in FIG. 15 represents the magnitude of the current. The horizontal axis of the graph represents elapsed time. For example, in the repeated processing of steps S330 to S340 shown in FIG. 14, the time during which the control device 20 passes current to each target group is, for example, 100 microseconds. That is, the control device 20 completes passing current to all 24 magnetized coils C within 400 microseconds and completes demagnetization of the variable flux magnet VM. At this time, the control device 20 passes current to each of the four groups so that the times during which current flows through the four groups do not overlap. Therefore, in the example shown in FIG. 15, the maximum value of the current passed by the control device 20 to the variable flux magnet module VMM is the magnitude indicated by I3 on the graph. Note that I3 is approximately six times the aforementioned I1. Timing T3 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 starts to pass current to group G1. Timing T4 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 finishes passing current to group G1. Timing T5 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 starts to pass current to group G2. Timing T6 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 finishes passing current to group G2. Timing T7 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 starts to pass current to group G3. Timing T8 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 finishes passing current to group G3. Timing T9 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 starts to pass current to group G4. Timing T10 shown in FIG. 15 indicates, for example, an example of the timing when the control device 20 finishes passing current to group G4.

On the other hand, if the control device 20 determines that the rotation speed of the rotating electric machine 10 is less than the predetermined threshold value (step S310-NO), it identifies the current magnetic force of the variable magnetic flux magnet VM of the variable magnetic flux magnet module VMM based on the magnetic force information stored in the memory unit of the control device 20, and determines whether the identified magnetic force is the first magnetic force (step S350).

If the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is the first magnetic force (step S350 - YES), it transitions to step S310 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

On the other hand, if the control device 20 determines that the magnetic force of the variable magnetic flux magnet VM is not the first magnetic force (step S350-NO), it selects one of the four groups as a target group and repeats the process of step S370 for each selected target group (step S360). Note that the order in which the four groups are selected one by one as a target group may be random or may be a predetermined order. The predetermined order may be any order.

After the target group is selected in step S360, the control device 20 passes current through the target group to magnetize the magnetically variable regions of each of the six magnetized coils C included in the target group (step S370). In this case, the control device 20 passes current through the target coils so that magnetic flux passes through the magnetically variable regions of each of the six magnetized coils C in the positive direction of the Z axis. As a result, the control device 20 magnetizes the magnetically variable regions of each of the six magnetized coils C in step S370. Note that the magnitude of the current passed by the control device 20 to the target group in step S370 is determined, for example, through prior simulation, theoretical calculations in electromagnetics, or repeated trial-and-error experiments so that the net magnetic force of the variable flux magnet VM becomes the first magnetic force when the magnetization of all the magnetically variable regions of each of the 24 magnetized coils C is complete. However, it may be determined by other methods. After processing in step S370, the control device 20 transitions to step S360 and selects the next target group. If there is no unselected group that can be selected as the next target group in step S360, the control device 20 ends the repeated processing of steps S360 to S370. The control device 20 then transitions to step S310 and again determines whether the rotation speed of the rotating electric machine 10 is equal to or greater than the predetermined threshold.

In this way, by repeating steps S360 to S370, the control device 20 increases the magnetic force of the variable magnetic flux magnet VM from the second magnetic force to the first magnetic force. At this time, the control device 20 passes current through each of the four groups so that the times at which current flows through the four groups do not overlap. This allows the control device 20 to change the magnetism of the variable magnetic flux magnet VM while preventing the magnetic fields of adjacent magnetized coils C from canceling each other out. In other words, the control device 20 can solve the problems caused by the arrangement of the 24 magnetized coils C on the first surface M1.

As described above, the control device 20 passes current through each of the one or more magnetization coils C included in the variable flux magnet module VMM in accordance with the rotation speed of the rotating electric machine 10, thereby changing the magnetization of the variable flux magnet VM. In this case, the control device 20 passes current through each of the four groups so that the times at which current flows through the four groups do not overlap. This allows the control device 20 to change the magnetization of the variable flux magnet VM while preventing the magnetic fields of adjacent magnetization coils C from canceling each other out. In other words, the control device 20 can solve the problems caused by the arrangement of the 24 magnetization coils C on the first surface M1.

<Modification 3 of the process in which the control device controls the variable magnetic flux magnet module>
Hereinafter, with reference to FIG. 16 , a third variation of the process in which the control device 20 controls the variable flux magnet module VMM will be described. In this third variation, the control device 20 changes the magnetic force of the variable flux magnet VM to one of three or more magnetic forces of different magnitudes depending on the rotation speed of the rotating electric machine 10. This allows the control device 20 to more finely adjust the magnetic force of the variable flux magnet. In this case, the storage unit of the control device 20 stores, for example, first correspondence information in which rotation speed range information is associated with magnetic force information indicating the magnetic force of the variable flux magnet VM for each of three or more pieces of rotation speed range information. Here, the rotation speed range information refers to information indicating the rotation speed range of the rotating electric machine 10. In this case, the storage unit of the control device 20 also stores, for example, second correspondence information in which magnetic force information is associated with first identification information and second identification information for each of three or more pieces of magnetic force information. The first identification information is information including identification information for identifying each of one or more magnetized coils C through which a current is passed so as to generate a magnetic field that penetrates the magnetization region in the negative direction of the Z axis. The second identification information is information including identification information for identifying each of one or more magnetized coils C through which a current is passed so as to generate a magnetic field that penetrates the magnetization region in the positive direction of the Z axis.

Figure 16 shows a third variation of the process flow in which the control device 20 controls the variable flux magnet module VMM. The variable flux magnet module VMM may be configured to include a control unit that executes at least some of the processes of the control device 20 described below. The variable flux magnet module VMM may also be configured integrally with the control device 20. In this case, the control device 20 functions as the control unit for the variable flux magnet module VMM. Below, as an example, a case will be described in which the control device 20 starts rotating the rotating electric machine 10 at a timing before the process of step S410 shown in Figure 16 is performed. Below, as an example, a case will be described in which information indicating the initial value of the magnetic force of the variable flux magnet VM of the variable flux magnet module VMM is stored as magnetic force information in a memory unit (not shown) of the control device 20. The control device 20, for example, repeatedly performs the process of the flowchart shown in Figure 16 until the rotation of the rotating electric machine 10 is stopped.

The control device 20 acquires an output signal at a predetermined sampling period from, for example, a Hall sensor (not shown) provided in the rotating electric machine 10, and determines the rotation speed of the rotating electric machine 10 based on the acquired output signal (step S410). The method for determining the rotation speed based on the output signal may be a known method or a method to be developed in the future.

Next, the control device 20 identifies rotation speed range information indicating a range including the rotation speed identified in step S410 from among the multiple rotation speed range information included in the first correspondence information stored in the memory unit of the control device 20. Then, the control device 20 identifies the magnetic force indicated by the magnetic force information associated with the identified rotation speed range information as the target magnetic force for changing the magnetic force of the variable magnetic flux magnet VM (step S420).

Next, the control device 20 identifies magnetic force information indicating the target magnetic force identified in step S420 from the magnetic force information included in the second correspondence information stored in the memory unit of the control device 20. The control device 20 then identifies the first identification information and the second identification information associated with the identified magnetic force information. The control device 20 identifies one or more magnetized coils C identified by the identified first identification information as demagnetization use magnetized coils, and identifies one or more magnetized coils C identified by the identified second identification information as magnetization use magnetized coils for magnetization (step S430). In Figure 16, the processing of step S430 is indicated by "identification of magnetized coils to be used."

Next, the control device 20 demagnetizes the magnetization change region of each of the one or more demagnetization use magnetized coils identified in step S430, and magnetizes the magnetization change region of each of the one or more magnetization use magnetized coils identified in step S430 (step S440). In Figure 16, the processing of step S440 is indicated by "magnetization." By processing step S440, the control device 20 can change the magnetic force of the variable magnetic flux magnet VM to the target magnetic force. After processing step S440, the control device 20 transitions to step S410 and again determines the rotation speed of the rotating electric machine 10.

As described above, the control device 20 changes the magnetic force of the variable flux magnet VM to one of three or more magnetic forces of different magnitudes depending on the rotation speed of the rotating electric machine 10. In this case, for example, when the control device 20 sets the magnetic force of the variable flux magnet VM to a first magnetic force, it passes current through one or more of the 24 magnetization coils C that are associated with the first magnetic force (i.e., at least one of one or more demagnetization use magnetization coils and one or more magnetization increase use magnetization coils), and when the control device 20 sets the magnetic force of the variable flux magnet VM to a second magnetic force, it passes current through one or more of the 24 magnetization coils C that are associated with the second magnetic force (i.e., at least one of one or more demagnetization use magnetization coils and one or more magnetization increase use magnetization coils). This allows the control device 20 to more precisely adjust the magnetic force of the variable flux magnet.

As described above, the variable flux magnet module according to the embodiment (variable flux magnet module VMM in the example described above) comprises a variable flux magnet (variable flux magnet VM in the example described above) and one or more coils (one or more magnetizing coils C in the example described above) arranged on at least a first surface (first surface M1 in the example described above) of the surfaces of the variable flux magnet. This allows for reduced individual variation in the variable flux magnet module.

Furthermore, the variable magnetic flux magnet module may be configured such that two or more coils (24 magnetization coils C in the example described above) are arranged on the first surface as one or more coils.

Furthermore, the variable magnetic flux magnet module may be configured such that a portion of the conductor wound as a first coil of two or more coils (e.g., magnetizing coil C-1 in the example described above) overlaps with a portion of the winding of a second coil (e.g., magnetizing coil C-2 in the example described above) that is different from the first coil of the two or more coils.

Furthermore, the variable magnetic flux magnet module may be configured such that a portion of the coil surface of a third coil (e.g., magnetization coil C-1 in the example described above) among the two or more coils overlaps with a portion of the coil surface of a fourth coil (e.g., magnetization coil C-2 in the example described above) that is different from the third coil among the two or more coils.

Furthermore, the variable magnetic flux magnet module may be configured such that one or more coils are arranged on a second surface (second surface M2 in the example described above) that is different from the first surface of the variable magnetic flux magnet.

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the second surface is the surface opposite the first surface.

Furthermore, the variable flux magnet module may be configured such that at least one of the one or more coils is contained within the outline of the first surface in a direction perpendicular to the first surface (the Z-axis direction in the example described above).

Furthermore, the variable magnetic flux magnet module may be configured to further include a magnetic body (magnetic body MB in the example described above).

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the magnetic body covers at least a portion of the surface of the variable magnetic flux magnet.

Furthermore, in the variable flux magnet module, the magnetic body may have a recess (recess CC in the example described above) that houses the variable flux magnet together with one or more coils arranged on the first surface, and the variable flux magnet may be housed in the recess together with one or more coils arranged on the first surface.

Furthermore, in the variable magnetic flux magnet module, two or more coils are arranged on the first surface as one or more coils, and the variable magnetic flux magnet module may further include a control unit (in the example described above, a control device 20 configured integrally with the variable magnetic flux magnet module VMM) that passes current through each of the two or more coils.

Furthermore, in the variable magnetic flux magnet module, the control unit may be configured to pass current through each of two or more coils so that the times when current flows through each of the two or more coils do not overlap.

Furthermore, in the variable magnetic flux magnet module, two or more coils are classified into two or more groups (in the example described above, four groups: group G1 to group G4), and the control unit may be configured to pass current through each of the two or more groups so that the times when current flows through the two or more groups do not overlap.

Furthermore, in the variable magnetic flux magnet module, when the magnetic force of the variable magnetic flux magnet is set to a first magnetic force, the control unit passes current through one or more first magnetic force coils (in the example described above, at least one of one or more demagnetization use coils and one or more magnetization use coils) among the two or more coils that are associated with the first magnetic force, and when the magnetic force of the variable magnetic flux magnet is set to a second magnetic force that is stronger than the first magnetic force, the control unit passes current through one or more second magnetic force coils (in the example described above, at least one of one or more demagnetization use coils and one or more magnetization use coils) among the two or more coils that are associated with the second magnetic force.

The above describes in detail an embodiment of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and modifications, substitutions, deletions, etc. may be made without departing from the spirit of this disclosure.

In addition, a program for realizing the functions of any of the components of the device described above may be recorded on a computer-readable recording medium, and the program may be loaded and executed by a computer system. Here, the device in question is, for example, the control device 20. Note that the term "computer system" here includes hardware such as the OS (Operating System) and peripheral devices. Furthermore, "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD (Compact Disk)-ROMs, as well as storage devices such as hard disks built into computer systems. Furthermore, "computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory within a computer system that acts as a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line.

The above program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. Here, the "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network such as the Internet or a communication line such as a telephone line.
The program may also be a program for realizing some of the functions described above, or may be a so-called differential file or differential program that can realize the functions described above in combination with a program already recorded in the computer system.

1... Rotating electric machine control system, 10... Rotating electric machine, 11... Rotor, 12... Stator, 20... Control device, C, C-1 to C-24... Magnetizing coil, M1... First surface, M2... Second surface, MB... Magnetic body, MG... Fixed magnet, VM... Variable flux magnet, VMM, VMM-1 to VMM-6... Variable flux magnet module

Claims (13)

a variable flux magnet;
a plurality of coils arranged on at least a first surface of the variable magnetic flux magnet and having coil surfaces parallel to each other ;
Equipped with
The plurality of coils are arranged in a matrix.
Variable flux magnet module. a portion of the conductor wound as a first coil of the plurality of coils overlaps with a portion of a winding of a second coil different from the first coil of the plurality of coils;
The variable flux magnet module of claim 1 . a part of a coil surface of a third coil among the plurality of coils overlaps with a part of a coil surface of a fourth coil different from the third coil among the plurality of coils;
The variable flux magnet module according to claim 2 . One or more coils are arranged on a second surface of the variable magnetic flux magnet that is different from the first surface.
The variable flux magnet module according to any one of claims 1 to 3 . The second surface is a surface opposite to the first surface.
The variable flux magnet module according to claim 4 . Further comprising a magnetic material,
A variable flux magnet module according to any one of claims 1 to 5 . the magnetic body covers at least a portion of the surface of the variable magnetic flux magnet;
The variable flux magnet module of claim 6 . the magnetic body has a recess that accommodates the variable magnetic flux magnet together with the plurality of coils arranged on the first surface,
The variable magnetic flux magnet is accommodated in the recess together with the plurality of coils arranged on the first surface.
8. The variable magnetic flux magnet module according to claim 6 or 7 . The variable magnetic flux magnet module further includes a control unit that applies current to each of the plurality of coils.
A variable flux magnet module according to any one of claims 1 to 8 . the control unit causes current to flow through each of the plurality of coils so that the times at which current flows through each of the plurality of coils do not overlap.
The variable flux magnet module of claim 9 . The plurality of coils are classified into two or more groups,
the control unit causes current to flow through each of the two or more groups so that times during which current flows through the two or more groups do not overlap.
The variable flux magnet module of claim 9 . When the magnetic force of the variable magnetic flux magnet is set to a first magnetic force, the control unit passes a current through one or more first magnetic force coils among the plurality of coils that are associated with the first magnetic force, and when the magnetic force of the variable magnetic flux magnet is set to a second magnetic force that is stronger than the first magnetic force, the control unit passes a current through one or more second magnetic force coils among the plurality of coils that are associated with the second magnetic force.
12. A variable flux magnet module according to any one of claims 9 to 11 . A variable flux magnet module according to any one of claims 1 to 12 ,
Rotating electric motor.