JP7762046B2 - 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; a first coil arranged on a first surface of the variable flux magnet; and a second coil having a coil surface with an area larger than the area of the coil surface of the first coil and generating a magnetic field that penetrates at least the first surface of the variable flux magnet, wherein the coil surface of the first coil is contained inside the coil surface of the second coil in a direction perpendicular to the first surface.

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. This is a diagram showing an example of a region on the first surface M1 where magnetization occurs when the magnetizing coil C-1 generates a magnetic field that penetrates the coil surface in the positive direction of the Z axis. This figure shows an example of an area on the first surface M1 where magnetization occurs when magnetization coil C-1 and magnetization coil C-2 each generate a magnetic field that penetrates the coil surface in the positive direction of the Z axis. This figure shows an example of an area on the first surface M1 where magnetization changes occur when each of the magnetization coils C-1 to C-3 generates a magnetic field that penetrates the coil surface in the positive direction of the Z axis. FIG. 10 is a diagram illustrating another example of the configuration of the variable magnetic flux magnet module VMM. FIG. 7 is a diagram showing an example of the magnetizing coil C-1 shown in FIG. 6. FIG. 7 is a diagram showing an example of the magnetizing coil C-2 shown in FIG. 6. FIG. 7 is a diagram showing an example of the magnetizing coil C-3 shown in FIG. 6. FIG. 10 is a side 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 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 three magnetizing coils C arranged on a first surface M1. FIG. 13 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. 12. 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.

<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 Fig. 2. Fig. 2 is a perspective view showing an example of the configuration of the variable magnetic flux magnet module VMM.

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 FIG. 2, the variable magnetic flux magnet VM is a flat, rectangular variable magnetic flux magnet. Note that the shape of the variable magnetic flux magnet VM may be other shapes instead of a flat, rectangular shape. The variable magnetic flux magnet VM may be composed of multiple variable magnetic flux magnet pieces, or may be composed of a single variable magnetic flux magnet piece.

Each of the M magnetized coils C generates a magnetic field that penetrates at least the first surface M1 of the surfaces of the variable magnetic flux magnet VM. Each of the M magnetized coils C may be any coil capable of generating a magnetic field that penetrates the first surface M1 when a current is passed through it. Below, as an example, we will describe a case where each of the M magnetized coils C is a spiral coil with a coil surface that is parallel (or nearly parallel) to the first surface M1, excluding tilt due to bending, distortion, etc. Here, the first surface M1 is the surface of the variable magnetic flux magnet VM that is on the positive side of the Z axis. The coil surface of a given magnetized coil C is an imaginary plane with a thickness that includes the conductor wound as that magnetized coil C and the opening of that magnetized coil C. The first surface M1 may be a surface of the variable magnetic flux magnet VM that is different from the surface on the positive side of the Z axis. Furthermore, some or all of the M magnetization coils C may be spiral coils having coil surfaces that are non-parallel to each other, or may be spiral coils having coil surfaces that are parallel to each other and non-parallel to the first plane M1.

Furthermore, the M magnetized coils C each have a different coil surface area. When the M magnetized coils C are arranged in ascending order of coil surface area, the coil surface of the i-th magnetized coil C in the direction perpendicular to the first plane M1 is included inside the coil surface of the (i+1)th magnetized coil C. Here, i represents an integer between 1 and M-1.

Furthermore, at least one of the M magnetized coils C is arranged on the first surface M1. That is, at least one of the M magnetized coils C is included inside the outline of the first surface M1 in a direction perpendicular to the first surface M1, i.e., in the Z-axis direction. For example, in a variable magnetic flux magnet module VMM, the magnetized coil C with the smallest coil surface area among the M magnetized coils C is arranged on the first surface M1. Also, for example, in a variable magnetic flux magnet module VMM, the magnetized coil C with the third smallest coil surface area among the M magnetized coils C is arranged on the first surface M1, along with the magnetized coil C with the second smallest coil surface area among the M magnetized coils C and the magnetized coil C with the smallest coil surface area among the M magnetized coils C.

As an example, the following describes a case where the variable flux magnet module VMM includes three magnetization coils C, magnetization coils C-1 to C-3, as the M magnetization coils C, as shown in FIG. 2. In the example shown in FIG. 2, magnetization coil C-1 is the magnetization coil C with the smallest coil surface area of the three magnetization coils C. In addition, in this example, magnetization coil C-2 is the magnetization coil C with the second smallest coil surface area of the three magnetization coils C. In addition, in this example, magnetization coil C-2 is the magnetization coil C with the largest coil surface area of the three magnetization coils C. Therefore, as shown in FIG. 2, the coil surface of magnetization coil C-1 is included inside the coil surface of magnetization coil C-2 in the direction perpendicular to first plane M1, i.e., in the Z-axis direction. In addition, as shown in FIG. 2, the coil surface of magnetization coil C-2 is included inside the coil surface of magnetization coil C-3 in the direction perpendicular to first plane M1, i.e., in the Z-axis direction.

In the example shown in FIG. 2, all three magnetized coils C are arranged on the first surface M1. In other words, in this example, each of the three magnetized coils C is included inside the outline of the first surface M1 in a direction perpendicular to the first surface M1, i.e., in the Z-axis direction. This allows each of the three magnetized coils C to more reliably generate a magnetic field that penetrates the first surface M1. Note that some of the three magnetized coils C may not be arranged on the first surface M1. In other words, some of the three magnetized coils C may have a coil surface that partially extends outside the outline of the first surface M1 in that direction. For example, if the conductor wound as the magnetizing coil C-3 is wound so as to surround the side surface of the variable magnetic flux magnet VM (that is, if the magnetizing coil C-3 is composed of a conductor wound so as to surround the side surface of the variable magnetic flux magnet VM), part of the coil surface of the magnetizing coil C-3 will protrude from the inside of the outline in that direction. However, even in this case, with the variable magnetic flux magnet module VMM, the coil surface of the magnetizing coil C-3 can be made parallel (or nearly parallel) to the first surface M1, and a magnetic field that penetrates the first surface M1 can be generated in the magnetizing coil C-3. Note that, when the first surface M1 is considered the front, the side surface of the variable flux magnet refers to the surface of the variable flux magnet VM that faces the first surface M1 (i.e., the surface of the variable flux magnet VM on the negative side of the Z axis) and the surface that connects the first surface M1 (i.e., the surface of the variable flux magnet VM that is perpendicular to the XY plane spanned by the X and Y axes).

Furthermore, the centers of the coil surfaces of magnetized coils C-1 to C-3 do not necessarily have to coincide in the direction perpendicular to first plane M1. However, in the example shown in FIG. 2, the centers of the coil surfaces of magnetized coils C-1 to C-3 coincide (or nearly coincide) in the direction perpendicular to first plane M1, excluding errors due to assembly, etc. In this case, the variable flux magnet module VMM can more reliably strengthen the magnetic field generated by magnetized coil C-2 near the center of the coil surface of magnetized coil C-2 using the magnetic field generated by magnetized coil C-1. Furthermore, in this case, the variable flux magnet module VMM can more reliably strengthen the magnetic field generated by magnetized coil C-3 near the center of the coil surface of magnetized coil C-3 using the magnetic field generated by magnetized coil C-2.

In a variable flux magnet module VMM configured as described above, when current flows through each of the three magnetized coils C arranged on the first surface M1, these three magnetized coils C generate a magnetic field that penetrates the first surface M1. In other words, in the variable flux magnet module VMM, magnetic flux representing the magnetic field generated by the three 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. For example, when a magnetized coil C generates a magnetic field that penetrates the coil surface 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 that magnetized coil C in the Z axis direction increases (i.e., the region is magnetized). On the other hand, for example, if a magnetized coil C generates a magnetic field that penetrates the coil surface in the negative direction of the Z axis, the magnetic force in the area of the variable magnetic flux magnet VM that overlaps with the magnetized coil C in the Z axis direction will decrease (i.e., the area will be 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, at least one of the three magnetized coils C is arranged on the first surface M1 of the variable flux magnet VM. As described above, this means that at least one of the three magnetized coils C is included inside the outline of the first surface M1 in the direction perpendicular to the first surface M1. In other words, in the variable flux magnet module VMM, the area of the coil surface of at least one of the three magnetized coils C can be made smaller than the area of the first surface M1. As a result, in the variable flux magnet module VMM, at least one magnetized coil C arranged on the first surface M1 can strengthen the magnetic field generated by the other magnetized coils C that penetrates near the center of the coil surface. As a result, the variable flux magnet module VMM can reduce the degree of variation in the strength of the magnetic field penetrating the first surface M1 compared to the degree of variation in the strength of the magnetic field penetrating the coil surfaces of the magnetized coils of the variable flux magnet module X. In other words, the variable flux magnet module VMM can reduce individual differences. This also means that the variable flux magnet module VMM can reduce individual differences among rotating electric machines 10 equipped with the variable flux magnet module VMM.

For example, in the variable flux magnet module VMM shown in FIG. 2, all three magnetizing coils C are arranged on the first surface M1. In this case, in this variable flux magnet module VMM, magnetizing coil C-2 is arranged inside the coil surface of magnetizing coil C-3, and magnetizing coil C-1 is arranged inside the coil surface of magnetizing coil C-2. Therefore, in this variable flux magnet module VMM, magnetizing coil C-2 can increase the strength of the magnetic field generated by magnetizing coil C-3 near the center of magnetizing coil C-3. Also, in this variable flux magnet module VMM, magnetizing coil C-1 can increase the strength of the magnetic field generated by magnetizing coil C-2 near the center of magnetizing coil C-2. As a result, the variable flux magnet module VMM can reduce the degree of variation in the strength of the magnetic field penetrating the first surface M1 compared to the degree of variation in the strength of the magnetic field penetrating the coil surfaces of the magnetized coils of the variable flux magnet module X. In other words, the variable flux magnet module VMM can reduce individual differences. This also means that the variable flux magnet module VMM can reduce individual differences among rotating electric machines 10 that include the variable flux magnet module VMM. This effect can be obtained in the same way in the variable flux magnet module VMM, even if, for example, only the magnetized coil C-3, or both the magnetized coils C-2 and C-3, are not arranged on the first surface M1, due to the presence of the magnetized coil C-1 arranged on the first surface M1. In addition to these three magnetization coils C, the variable magnetic flux magnet module VMM may also be configured such that one or more other magnetization coils having coil surfaces that do not overlap with the coil surfaces of these three magnetization coils C are arranged on the first surface M1.

Here, Figure 3 is a diagram showing an example of a region on the first surface M1 where magnetization changes when the magnetizing coil C-1 generates a magnetic field that penetrates the coil surface in the positive direction of the Z axis. In this case, the magnetic field generated by the magnetizing coil C-1 penetrates the region on the first surface M1 that overlaps with the coil surface of the magnetizing coil C-1 in the Z axis direction in the positive direction of the Z axis. As a result, the magnetic force in this region increases. The hatched region R1P in Figure 3 shows an example of a region where the magnetic force increases in this way. As shown in Figure 3, region R1P is the region on the first surface M1 that overlaps with the coil surface of the magnetizing coil C-1 in the Z axis direction. On the other hand, in this case, the magnetic field generated by the magnetizing coil C-1 penetrates the region on the first surface M1 outside the coil surface of the magnetizing coil C-1 in the Z axis direction in the negative direction of the Z axis. As a result, the magnetic force in this region decreases. The hatched region R1N in FIG. 3 is an example of a region where the magnetic force is reduced in this case. As shown in FIG. 3, region R1N is a region on the first surface M1 that is outside the coil surface of the magnetized coil C-1 in the Z-axis direction. More specifically, region R1N is a region on the first surface M1 that is surrounded by the magnetized coil C-1 and the magnetized coil C-2 and that is in contact with the magnetized coil C-1 but not with the magnetized coil C-2. The area of region R1P is larger than the area of region R1N. Therefore, in this case, the net magnetic force of the variable flux magnet VM increases. Furthermore, the coil surface of the magnetized coil C-1 can be made smaller than the area of the first surface M1. Therefore, in this case, the variable flux magnet module VMM can reduce the degree of variation within the coil surface of the magnetic field that penetrates the coil surface of the magnetized coil C-1 in the positive direction of the Z-axis. In other words, the variable flux magnet module VMM can reduce individual differences.

Figure 4 also shows an example of a region on the first surface M1 where magnetization changes when magnetizing coil C-1 and magnetizing coil C-2 each generate a magnetic field that penetrates the coil surface in the positive direction of the Z axis. In this case, the magnetic field generated by magnetizing coil C-1 penetrating the region in the negative direction of the Z axis is canceled out by the magnetic field generated by magnetizing coil C-2 penetrating the region in the positive direction of the Z axis. Therefore, in this case, the net magnetic field generated by magnetizing coil C-1 and magnetizing coil C-2 penetrates the region on the first surface M1 that overlaps with the coil surface of magnetizing coil C-2 in the Z axis direction in the positive direction of the Z axis. As a result, the magnetic force in that region increases. Region R2P, shown hatched in Figure 4, is an example of a region where magnetic force increases in this way. As shown in Figure 4, region R2P is the region on the first surface M1 that overlaps with the coil surface of magnetizing coil C-2 in the Z axis direction. On the other hand, in this case, the magnetic field generated by the magnetized coil C-2 penetrates the region on the first surface M1 that is outside the coil surface of the magnetized coil C-2 in the Z-axis direction toward the negative direction of the Z-axis. As a result, the magnetic force in this region decreases. The hatched region R2N in FIG. 4 shows an example of a region where the magnetic force decreases in this case. As shown in FIG. 4, region R2N is the region on the first surface M1 that is outside the coil surface of the magnetized coil C-2 in the Z-axis direction. More specifically, region R2N is the region on the first surface M1 surrounded by the magnetized coil C-2 and the magnetized coil C-3 that is in contact with the magnetized coil C-2 but not with the magnetized coil C-3. The area of region R2P is larger than the area of region R2N. Therefore, in this case, the net magnetic force of the variable flux magnet VM increases. Additionally, in the Z-axis direction, the coil surface of magnetized coil C-1 is included inside the coil surface of magnetized coil C-2. Therefore, in this case, the variable flux magnet module VMM can reduce the degree of variation within the coil surface of the magnetic field that penetrates the coil surface of magnetized coil C-2 in the positive direction of the Z-axis by using the magnetic field that penetrates the coil surface of magnetized coil C-1 in the positive direction of the Z-axis. In other words, the variable flux magnet module VMM can reduce individual variations.

Figure 5 also shows an example of a region on the first surface M1 where magnetization changes occur when magnetization coils C-1 to C-3 each generate a magnetic field that penetrates the coil surface in the positive direction of the Z axis. In this case, the magnetic field generated by magnetization coil C-1 to penetrate the region in the negative direction of the Z axis is canceled out by the magnetic fields generated by magnetization coils C-2 and C-3 to penetrate the region in the positive direction of the Z axis. In addition, the magnetic field generated by magnetization coil C-2 to penetrate the region in the negative direction of the Z axis is canceled out by the magnetic field generated by magnetization coil C-3 to penetrate the region in the positive direction of the Z axis. Therefore, in this case, the net magnetic field generated by magnetization coils C-1 to C-3 penetrates the region on the first surface M1 that overlaps with the coil surface of magnetization coil C-3 in the Z axis direction in the positive direction of the Z axis. As a result, the magnetic force in that region increases. The hatched region R3P in FIG. 5 is an example of a region where the magnetic force is increased in this way. As shown in FIG. 5, region R3P is a region on the first surface M1 that overlaps with the coil surface of the magnetizing coil C-3 in the Z-axis direction. Meanwhile, in this case, the magnetic field generated by the magnetizing coil C-3 penetrates the region outside the first surface M1 toward the negative direction of the Z-axis. As a result, the magnetic force of the variable magnetic flux magnet VM is not reduced by this magnetic field. Therefore, in this case, the net magnetic force of the variable magnetic flux magnet VM increases. Furthermore, in the Z-axis direction, the coil surface of the magnetizing coil C-2 is included inside the coil surface of the magnetizing coil C-3. Furthermore, in the Z-axis direction, the coil surface of the magnetizing coil C-1 is included inside the coil surface of the magnetizing coil C-2. For this reason, in this case, the variable flux magnet module VMM can more reliably reduce the degree of variation within the coil plane of the magnetic field that penetrates the coil plane of magnetized coil C-3 in the positive direction of the Z axis by using the magnetic field that penetrates the coil planes of magnetized coils C-1 and C-2 in the positive direction of the Z axis. In other words, the variable flux magnet module VMM can more reliably reduce individual differences.

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, with the variable flux magnet module VMM, the size of each magnetized coil C arranged on the first surface M1 can be adjusted depending on the application. Furthermore, the variable flux magnet module VMM can also adjust, through control, the number of magnetized coils C that generate a magnetic field that penetrates the coil surface in the positive direction of the Z axis, the number of magnetized coils C that generate a magnetic field that penetrates the coil surface in the negative direction of the Z axis, and the number of magnetized coils C that do not generate a magnetic field. Therefore, with the variable flux magnet module VMM, the amount of change in the magnetic force of the variable flux magnet VM can be adjusted even after manufacture.

In the example shown in FIG. 2, 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 that penetrates the coil surface also 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 an adhesive or the like. Note that some or all of the three 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.

In the example shown in FIG. 2, the conductors wound as each of the three magnetized coils C do not overlap each other. However, as shown in FIG. 6, the conductors wound as each of the three magnetized coils C may partially overlap each other. FIG. 6 is a diagram showing another example of the configuration of a variable flux magnet module VMM. In the variable flux magnet module VMM shown in FIG. 6, the length of the side in the X-axis direction of the first surface M1 is shorter than the length of the side in the X-axis direction of the first surface M1 shown in FIG. 2. In addition, in this variable flux magnet module VMM, the length of the side in the X-axis direction of each of the three magnetized coils C is approximately the same as the length of the side in the X-axis direction of the first surface M1. For this reason, in FIG. 6, each of the magnetized coils C-1 to C-3 shown in FIGS. 7 to 9 is arranged on the first surface M1. FIG. 7 is a diagram showing an example of the magnetized coil C-1 shown in FIG. 6. FIG. 8 is a diagram showing an example of the magnetized coil C-2 shown in FIG. 6. FIG. 9 is a diagram showing an example of the magnetized coil C-3 shown in FIG. 6. The length in the X-axis direction of the magnetized coil C-3 shown in FIG. 9 is the same as the length in the X-axis direction of the magnetized coil C-2 shown in FIG. 8. Meanwhile, the length in the Y-axis direction of the magnetized coil C-3 shown in FIG. 9 is longer than the length in the Y-axis direction of the magnetized coil C-2 shown in FIG. 8. Therefore, the area of the magnetized coil C-3 shown in FIG. 9 is larger than the area of the magnetized coil C-2 shown in FIG. 8. Furthermore, the length in the X-axis direction of the magnetized coil C-2 shown in FIG. 8 is the same as the length in the X-axis direction of the magnetized coil C-1 shown in FIG. 7. Meanwhile, the length in the Y-axis direction of the magnetized coil C-2 shown in FIG. 8 is longer than the length in the Y-axis direction of the magnetized coil C-1 shown in FIG. 7. Therefore, the area of the magnetized coil C-2 shown in FIG. 8 is larger than the area of the magnetized coil C-1 shown in FIG. 7. Therefore, in the example shown in FIG. 6, the coil plane of the magnetized coil C-1 is included in the coil plane of the magnetized coil C-2 in a direction perpendicular to the coil plane. However, in this example, a portion of the conductor wound as magnetizing coil C-1 overlaps a portion of the conductor wound as magnetizing coil C-2. Also, in this example, the coil plane of magnetizing coil C-2 is included in the coil plane of magnetizing coil C-3 in a direction perpendicular to the coil plane. However, in this example, a portion of the conductor wound as magnetizing coil C-2 overlaps a portion of the conductor wound as magnetizing coil C-3. In this way, even in a configuration in which the conductors wound as each of the three magnetizing coils C partially overlap each other, the variable flux magnet module VMM can reduce the degree of variation in the magnetic fields generated by each of the three magnetizing coils C that penetrate the first surface M1 in the positive or negative direction of the Z axis. In other words, the variable flux magnet module VMM can reduce individual variations.

<Variation 1 of the configuration of the variable magnetic flux magnet module>
Below, a first modified example of the configuration of the variable flux magnet module VMM will be described with reference to FIG. 10 . In this first modified example, in addition to the first surface M1, one or more magnetized coils C may be arranged on a second surface M2 different from the first surface M1. Hereinafter, for convenience of explanation, among the regions of the variable flux magnet VM, a region that overlaps with a certain magnetized coil C in the Z-axis direction (i.e., a region that overlaps with the coil surface of the magnetized coil C) will be referred to as the magnetized region of the magnetized coil C. Also, below, as an example, a case will be described in which the second surface M2 is a surface facing the first surface M1, i.e., a 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 other than the first surface M1 and the surface of the variable flux magnet VM on the negative side of the Z-axis. FIG. 10 is a side view showing a first modified example of the configuration of the variable magnetic flux magnet module VMM.

In the variable magnetic flux magnet VM shown in FIG. 10, three magnetized coils C, magnetized coils C-1 to C-3, are arranged on the first surface M1, and three magnetized coils C, magnetized coils C-4 to C-6, are arranged on the second surface M2. 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. 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 separate conductors. The arrangement of the three magnetized coils C on the second surface M2 may be the same as or different from the arrangement of the three magnetized coils C on the first surface M1. In the example shown in FIG. 10, the arrangement of the three magnetized coils C on the second surface M2 is the same as the arrangement of the three magnetized coils C on the first surface M1. That is, in this example, the outline of magnetized coil C-1 and the outline of magnetized coil C-4 almost completely overlap in the Z-axis direction. Also, in this example, the outline of magnetized coil C-2 and the outline of magnetized coil C-5 almost completely overlap in the Z-axis direction. Also, in this example, the outline of magnetized coil C-3 and the outline of magnetized coil C-6 almost completely overlap in the Z-axis direction.

The arrangement of the three magnetizing coils C on the first surface M1 may be a combination of the arrangements shown in Figures 2 and 6. Furthermore, the arrangement of one or more magnetizing coils C on the second surface M2 may be a combination of the arrangements shown in Figures 2 and 6.

<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. 11. In this second modified example, the variable magnetic flux magnet module VMM includes a fixed magnet MG in addition to a variable magnetic flux magnet VM and three magnetized coils C. Fig. 11 is a perspective view showing the second modified example 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 11, 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 variable flux magnet VM from the three magnetized coils C in the direction in which the variable flux magnet VM and the three magnetized coils C are stacked. In the example shown in FIG. 11 , the fixed magnet MG is arranged on the opposite side of the variable flux magnet VM from the three magnetized coils C in the Z-axis direction so as to overlap with at least a portion of the three magnetized coils C. For example, as shown in FIG. 11 , the fixed magnet MG is arranged on the second surface M2 of the variable flux magnet VM. In the example shown in FIG. 11 , 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 3 of the configuration of the variable magnetic flux magnet module>
The following describes a third modification of the configuration of the variable flux magnet module VMM. In this third modification, the variable flux magnet module VMM includes a magnetic body MB in addition to the variable flux magnet VM and three 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 three 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 12 is a diagram showing an example of the variable flux magnet VM housed in the recess CC of the magnetic body MB along with three magnetized coils C arranged on the first surface M1. Figure 13 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 12. However, in Figures 12 and 13, the variable flux magnet VM shown in Figure 6 is shown as an example of the variable flux magnet VM housed in the recess CC.

As shown in FIG. 12, 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. 14 . FIG. 14 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. 14 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. 14, 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 three magnetized coils C so that the magnetic flux passes through the magnetized region of each of the three 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 three 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 it 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 three magnetized coils C so that the magnetic flux passes through the magnetized region of each of the three 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 three 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 becomes 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 the three 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. 15 , a first variation of the process in which the control device 20 controls the variable flux magnet module VMM will be described. In this first variation, the control device 20 passes current through each of the three magnetized coils C so that the times at which current flows through each of the three magnetized coils C do not overlap. At this time, the control device 20 passes current through each of the three magnetized coils C, for example, in ascending order of coil surface area. This allows the control device 20 to reduce the maximum value of current passed through the magnetized coils C when magnetizing 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. Note that the order in which current is passed through each of the three magnetized coils C may be different. FIG. 15 is a diagram showing a first variation of the process flow 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 of 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 processing of step S210 shown in Fig. 15 is performed. Also, 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 storage unit (not shown) of the control device 20. For example, the control device 20 repeatedly performs the processing of the flowchart shown in Fig. 15 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. 14, 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 three magnetized coils C provided in the variable magnetic flux magnet module VMM as a target coil one by one in order of smallest coil surface area, and repeats the process of step S240 for each selected target coil (step S230). Note that the order in which each of the three magnetized coils C is selected as a target coil one by one may be random or may be another predetermined order. The other 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 all the magnetically variable regions of the three magnetized coils C have been demagnetized. However, it may also 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 each of the three magnetized coils C so that the time during which current flows through each of the three 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 during the magnetization of the variable flux magnet VM. This can be clearly understood by looking at Figure 16. Figure 16 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 16 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 16, 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 three magnetized coils C. In this case, the control device 20 completes the flow of current through all three magnetized coils C within 300 microseconds, completing the demagnetization of the variable flux magnet VM. At this time, the control device 20 flows current through each of the three magnetized coils C so that the times at which current flows through each of the three magnetized coils C do not overlap. Therefore, in the example shown in FIG. 16, 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. 14, the control device 20 flows current through all three 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 three times I1. In other words, when the control device 20 performs the processing of the flowchart shown in FIG. 15, the control device 20 can reduce the maximum value of the current that passes through the magnetized 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 three magnetized coils C provided in the variable magnetic flux magnet module VMM as a target coil one by one in order of smallest coil surface area, and repeats the process of step S270 for each selected target coil (step S260). Note that the order in which each of the three magnetized coils C is selected as a target coil one by one may be random or may be another predetermined order. The other predetermined 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). In this case, the control device 20 passes a current through the target coil so that magnetic flux passes through the magnetization region of the target coil in the positive direction of the Z axis. As a result, the control device 20 magnetizes the magnetization region of the target coil in step S270. Note that 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, repeated trial and error experiments, etc., 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 three 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 three magnetized coils C so that the times at which current flows through each of the three magnetized coils C do 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 three magnetization coils C so that the times at which current flows through each of the three 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. 17 , 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 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 range of the rotation speed 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 17 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 17 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 17 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 S310). 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 S310 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 S320).

Next, the control device 20 identifies magnetic force information indicating the target magnetic force identified in step S320 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 coils to be used for magnetization (step S330). In Figure 17, the processing of step S330 is indicated by "identifying magnetized coils to be used." For example, if the target magnetic force is a third magnetic force that is weaker than the aforementioned second magnetic force, the one or more magnetized coils C identified by the first identification information associated with the magnetic force information indicating the third magnetic force are magnetized coils C-1. On the other hand, for example, in this case, the one or more magnetized coils C identified by the second identification information associated with the magnetic force information indicating the third magnetic force are magnetized coil C-2 and magnetized coil C-3. Also, for example, if the target magnetic force is a second magnetic force stronger than the third magnetic force, the one or more magnetized coils C identified by the first identification information associated with the magnetic force information indicating the second magnetic force are magnetized coil C-1 and magnetized coil C-2. On the other hand, for example, in this case, the one or more magnetized coils C identified by the second identification information associated with the magnetic force information indicating the second magnetic force are magnetized coil C-3. Also, for example, if the target magnetic force is a first magnetic force stronger than the second magnetic force, the one or more magnetized coils C identified by the first identification information associated with the magnetic force information indicating the first magnetic force are magnetized coils C-1 to C-3. On the other hand, for example, in this case, there is not one or more magnetized coils C identified by the second identification information associated with the magnetic force information indicating the first magnetic force.

Next, the control device 20 demagnetizes the magnetization change region of each of the one or more demagnetization use magnetized coils identified in step S330, and magnetizes the magnetization change region of each of the one or more magnetization use magnetized coils identified in step S330 (step S340). In Figure 17, the processing of step S340 is indicated by "magnetization." By processing step S340, the control device 20 can change the magnetic force of the variable magnetic flux magnet VM to the target magnetic force. After processing step S340, the control device 20 transitions to step S310 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, the control device 20 selects one or more magnetized coils C from among the three magnetized coils C to which current is to be passed depending on the target magnetic force, and passes current through the selected one or more magnetized coils C. 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), a first coil (for example, magnetized coil C-1 in the example described above) arranged on a first surface of the variable flux magnet (first surface M1 in the example described above), and a second coil (for example, magnetized coil C-2 in the example described above) that has a coil surface with an area larger than the area of the coil surface of the first coil and generates a magnetic field that penetrates at least the first surface of the variable flux magnet, with the coil surface of the first coil being included inside the coil surface of the second coil in the direction perpendicular to the first surface (the Z-axis direction in the example described above). This allows for reduced individual variation in variable flux magnet modules.

Furthermore, the variable magnetic flux magnet module may be configured such that the first coil is contained within the outline of the first surface in a direction perpendicular to the first surface.

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

Furthermore, the variable magnetic flux magnet module may be configured such that a portion of the conductor wound as the first coil overlaps a portion of the conductor wound as the second coil.

Furthermore, in the variable flux magnet module, the second coil may be composed of a conductor wound to surround the side surface of the variable flux magnet, and the side surface of the variable flux magnet may be the surface that connects the first surface to the surface of the variable flux magnet that faces the first surface (in the example described above, the second surface M2), when the first surface is the front.

Furthermore, the variable magnetic flux magnet module may be configured such that one or more third coils (in the example described above, magnetizing coils C-4 to C-6) that generate a magnetic field penetrating at least the second surface of the variable magnetic flux magnet are arranged on a second surface of the variable magnetic flux magnet that is different from the first surface.

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 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 the first coil and second coil, and the variable flux magnet may be housed in the recess together with the first coil and second coil.

The variable magnetic flux magnet module may also be configured to 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 first coil and the second coil.

Furthermore, in the variable magnetic flux magnet module, the control unit may be configured to pass current through each of the first coil and the second coil so that the times when current flows through each of the first coil and the second coil do not overlap.

Furthermore, in the variable magnetic flux magnet module, the control unit may be configured to pass current through the first coil and the second coil in ascending order of coil surface area, so that the times when current flows through the first coil and the second coil do not overlap.

Furthermore, the variable magnetic flux magnet module may be configured to include two or more coils that generate a magnetic field that penetrates at least a first surface of the surfaces of the variable magnetic flux magnet, the first coil and the second coil being included in the two or more coils, and when changing the magnetic force of the variable magnetic flux magnet to a target magnetic force, the control unit may select one or more coils from the two or more coils to which a current is to be passed according to the target magnetic force, and pass a current through the selected one or more coils.

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-6... Magnetized 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 (15)

a variable flux magnet;
a first coil disposed on a first surface of the variable magnetic flux magnet;
a second coil having a coil surface with an area larger than that of the first coil, and generating a magnetic field penetrating at least the first surface of the surfaces of the variable magnetic flux magnet;
Equipped with
a coil surface of the first coil is parallel to a coil surface of the second coil, and a center of the first coil coincides with a center of the second coil in a direction perpendicular to the first surface, and is included inside the coil surface of the second coil;
Variable flux magnet module. the first coil is included inside the outline of the first surface in a direction perpendicular to the first surface;
The variable flux magnet module of claim 1 . The second coil is disposed on the first surface.
The variable flux magnet module of claim 1 . a portion of the conductor wound as the first coil overlaps a portion of the conductor wound as the second coil;
The variable flux magnet module according to any one of claims 1 to 3. the second coil is formed of a conductor wound so as to surround a side surface of the variable magnetic flux magnet,
When the first surface is defined as the front, the side surface of the variable magnetic flux magnet refers to a surface of the variable magnetic flux magnet that faces the first surface and a surface that connects the first surface.
The variable flux magnet module of claim 1 . One or more third coils are arranged on a second surface of the variable magnetic flux magnet that is different from the first surface, and generate a magnetic field that penetrates at least the second surface of the variable magnetic flux magnet.
A variable flux magnet module according to any one of claims 1 to 5. The second surface is a surface opposite to the first surface.
The variable flux magnet module of claim 6. Further comprising a magnetic material,
A variable flux magnet module according to any one of claims 1 to 7. the magnetic body covers at least a portion of the surface of the variable magnetic flux magnet;
The variable flux magnet module of claim 8 . the magnetic body has a recess that accommodates the variable magnetic flux magnet together with the first coil and the second coil,
The variable magnetic flux magnet is housed in the recess together with the first coil and the second coil.
10. The variable magnetic flux magnet module according to claim 8 or 9. Further comprising a control unit that applies a current to each of the first coil and the second coil.
A variable flux magnet module according to any one of claims 1 to 10. the control unit causes current to flow through the first coil and the second coil, respectively, so that times when currents flow through the first coil and the second coil do not overlap.
The variable flux magnet module of claim 11. the control unit causes current to flow through the first coil and the second coil in ascending order of coil surface area so that times when current flows through the first coil and the second coil do not overlap.
13. The variable flux magnet module of claim 12. two or more coils that generate a magnetic field that penetrates at least the first surface of the surfaces of the variable magnetic flux magnet;
the first coil and the second coil are included in the two or more coils,
When changing the magnetic force of the variable magnetic flux magnet to a target magnetic force, the control unit selects one or more coils to which a current is to be passed from among the two or more coils in accordance with the target magnetic force, and passes a current through the selected one or more coils.
14. A variable flux magnet module according to any one of claims 11 to 13. 15. A variable flux magnet module according to claim 1,
Rotating electric motor.