JP7777427B2 - 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 magnet section that includes a variable flux magnet and a magnetization coil made of a conductor wound around the side of the magnet section (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 rotation speed exceeds a predetermined threshold, a rotating electric machine such as that described in Non-Patent Document 1 demagnetizes the variable flux magnets included in the magnet unit by passing current through the magnetizing coils of the variable flux magnet module provided in the rotating electric machine, thereby demagnetizing the magnet unit and achieving field weakening. This allows the rotating electric machine to improve its efficiency. However, it is known that the magnetic force of the variable flux magnet in this variable flux magnet module can change significantly with even slight differences in the magnitude of the current passed through the magnetizing coils. For this reason, it can be difficult to change the magnetic force of the magnet unit in three or more stages with this variable flux magnet module. In other words, it can be difficult to fine-tune the magnetic force of the magnet unit with this variable flux magnet module.

This disclosure was made in consideration of these circumstances, and aims to provide a variable magnetic flux magnet module and a rotating electric machine that can fine-tune the magnetic force of the magnet section.

One aspect of the present disclosure is a variable flux magnet module comprising a magnet unit having a first surface and a coil that generates a magnetic field that penetrates the first surface, the magnet unit including a first magnet unit including a first variable flux magnet having an eleventh surface and a second magnet unit including a second variable flux magnet having a twelfth surface, the eleventh surface and the twelfth surface constituting at least a portion of the first surface, and the magnetic properties of the second magnet unit being different from the magnetic properties of the first magnet unit.

This disclosure allows for fine adjustment of the magnetic force of the magnet unit.

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 diagram showing an example of the magnetic characteristics of each of the four magnet portions included in the magnet portion MG. FIG. 10 is a diagram showing a first modified example of the configuration of the variable magnetic flux magnet module VMM. A figure showing another example of the magnetic properties of each of the four magnet parts included in the magnet part MG. 10 is a diagram showing an example of a state in which a magnet portion MG is housed in a recess CC of a magnetic body MB together with a magnetized coil C. FIG. 8 is a diagram showing an example of a state in which the magnet portion MG is taken out from the recess CC of the magnetic body MB shown in FIG. 7. 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.

<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 equipped with a magnet section MG that includes a variable flux magnet VM. The 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, the variable flux magnet VM included in the magnet section MG of the variable flux magnet module VMM is demagnetized to demagnetize the magnet section MG and achieve field weakening of the rotating electric machine 10.

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. Note that 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 changes the magnetism of the magnet section MG of the variable magnetic flux magnet module VMM provided in the rotating electric machine 10 according to the determined rotation speed.

Here, it is known that in a variable flux magnet module X (such as a conventional variable flux magnet module) that is different from the variable flux magnet module VMM, the magnetic force of the variable flux magnet included in the magnet unit of the variable flux magnet module X can change significantly due to slight differences in the magnitude of the current flowing through the magnetizing coil that generates the magnetic field applied to the magnet unit. For this reason, in a variable flux magnet module X, it can be difficult to change the magnetic force of the magnet unit in three or more stages. In other words, it can be difficult to fine-tune the magnetic force of the magnet unit of the variable flux magnet module X.

In contrast, the variable flux magnet module VMM can discretely change the magnetic force of the magnet section MG in three or more stages. Therefore, the control device 20 can change the magnetic force of the magnet section MG of the variable flux magnet module VMM provided in the rotating electric machine 10 to a magnetic force corresponding to the specified rotation speed of the rotating electric machine 10. For example, when the rotation speed is a predetermined first rotation speed, the control device 20 sets the magnetic force of the magnet section MG to a first magnetic force. That is, when the rotation speed is the first rotation speed and the magnetic force of the magnet section MG is weaker than the first magnetic force, the control device 20 magnetizes the magnet section MG. Furthermore, when the rotation speed is the first rotation speed and the magnetic force of the magnet section MG is stronger than the first magnetic force, the control device 20 demagnetizes the magnet section MG. Furthermore, when the rotation speed is the first rotation speed and the magnetic force of the magnet section MG is the first magnetic force, the control device 20 does not change the magnetic force of the magnet section MG. Furthermore, for example, when the rotation speed is a second rotation speed that is higher than the first rotation speed, the control device 20 sets the magnetic force of the magnet unit MG to a second magnetic force that is weaker than the first magnetic force. That is, when the rotation speed is the second rotation speed and the magnetic force of the magnet unit MG is weaker than the second magnetic force, the control device 20 magnetizes the magnet unit MG. Furthermore, when the rotation speed is the second rotation speed and the magnetic force of the magnet unit MG is stronger than the second magnetic force, the control device 20 demagnetizes the magnet unit MG. Furthermore, when the rotation speed is the second rotation speed and the magnetic force of the magnet unit MG is the second magnetic force, the control device 20 does not change the magnetic force of the magnet unit MG. Furthermore, for example, when the rotation speed is a third rotation speed that is higher than the second rotation speed, the control device 20 sets the magnetic force of the magnet unit MG to a third magnetic force that is weaker than the second magnetic force. That is, when the rotation speed is the third rotation speed and the magnetic force of the magnet unit MG is weaker than the third magnetic force, the control device 20 magnetizes the magnet unit MG. Furthermore, when the rotation speed is the third rotation speed and the magnetic force of the magnet unit MG is stronger than the third magnetic force, the control device 20 demagnetizes the magnet unit MG. Furthermore, when the rotation speed is the third rotation speed and the magnetic force of the magnet unit MG is the third magnetic force, the control device 20 does not change the magnetic force of the magnet unit MG. Through this control, the control device 20 can achieve field weakening in the rotating electric machine 10 and improve the efficiency of the rotating electric machine 10. The control device 20 may also be configured to change the magnetic force of the magnet unit MG in two discrete 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 magnet section MG including a variable flux magnet VM, and a magnetizing coil C. In the example shown in Figures 2 and 3, the variable flux magnet module VMM comprises one magnetizing coil C, but it may alternatively be configured to comprise two or more magnetizing coils C.

The magnet part MG has a first surface M1. In the example shown in Figures 2 and 3, the first surface M1 is the surface of the magnet part MG on the positive side of the Z axis. However, the first surface M1 may be any surface of the magnet part MG other than the surface on the positive side of the Z axis.

The magnet unit MG includes two or more magnet units with different magnetic properties. In the example shown in Figures 2 and 3, the magnet unit MG includes four magnet units, MG1 to MG4, with different magnetic properties. Note that some of these four magnet units may have the same magnetic properties. The magnetic properties of these four magnet units will be described later.

The magnet section MG1 includes at least a variable magnetic flux magnet VM1. The variable magnetic flux magnet VM1 is a variable magnetic flux magnet that constitutes part of the variable magnetic flux magnet VM described above. The variable magnetic flux magnet VM1 is also a variable magnetic flux magnet that has an eleventh surface M11 that constitutes part of the first surface M1. In the example shown in Figures 2 and 3, the magnet section MG1 includes a fixed magnet FM1 in addition to the variable magnetic flux magnet VM1.

The variable magnetic flux magnet VM1 is a variable magnetic flux magnet with a flat, rectangular shape. Note that the shape of the variable magnetic flux magnet VM1 may be other shapes instead of a flat, rectangular shape. The variable magnetic flux magnet VM1 may be composed of multiple variable magnetic flux magnet pieces, or may be composed of a single variable magnetic flux magnet piece.

The fixed magnet FM1 may be any permanent magnet as long as its magnetic force changes little when a magnetic field is applied. In the example shown in Figures 2 and 3, the fixed magnet FM1 is a flat, rectangular magnet. In this example, the fixed magnet FM1 has a shape and size such that its outline matches (or nearly matches) the outline of the variable magnetic flux magnet VM1 in the direction perpendicular to the first surface M1, i.e., the Z-axis direction. Note that the fixed magnet FM1 may also be configured so that its outline does not match the outline of the variable magnetic flux magnet VM1 in this direction. The shape of the fixed magnet FM1 may also be other shapes instead of a flat, rectangular shape.

The fixed magnet FM1 is located on the opposite side of the first surface M1, sandwiching the variable flux magnet VM1, in a direction perpendicular to the first surface M1. In the example shown in Figures 2 and 3, the variable flux magnet VM1 and the fixed magnet FM1 are in contact. That is, the fixed magnet FM1 is stacked with the variable flux magnet VM1 in a direction perpendicular to the first surface M1. Note that the fixed magnet FM1 may be spaced apart from the variable flux magnet VM1. In this case, the fixed magnet FM1 may be parallel to the variable flux magnet VM1, or may be non-parallel to the variable flux magnet VM1.

The magnet section MG2 includes at least a variable magnetic flux magnet VM2. The variable magnetic flux magnet VM2 is a variable magnetic flux magnet that constitutes part of the variable magnetic flux magnet VM. The variable magnetic flux magnet VM2 is also a variable magnetic flux magnet that has a twelfth surface M12 that constitutes part of the first surface M1. In the example shown in Figures 2 and 3, the magnet section MG2 includes a fixed magnet FM2 in addition to the variable magnetic flux magnet VM2.

The variable magnetic flux magnet VM2 is a variable magnetic flux magnet with a flat, rectangular shape. Note that the shape of the variable magnetic flux magnet VM2 may be other shapes instead of a flat, rectangular shape. The variable magnetic flux magnet VM2 may be composed of multiple variable magnetic flux magnet pieces, or may be composed of a single variable magnetic flux magnet piece.

The fixed magnet FM2 may be any permanent magnet as long as its magnetic force does not change when a magnetic field is applied. In the example shown in Figures 2 and 3, the fixed magnet FM2 is a flat, rectangular magnet. In this example, the fixed magnet FM2 has a shape and size such that its outline matches (or nearly matches) the outline of the variable magnetic flux magnet VM2 in the direction perpendicular to the first surface M1, i.e., the Z-axis direction. Note that the fixed magnet FM2 may also be configured so that its outline does not match the outline of the variable magnetic flux magnet VM2 in this direction. The shape of the fixed magnet FM2 may also be other shapes instead of a flat, rectangular shape.

The fixed magnet FM2 is located on the opposite side of the variable flux magnet VM2 from the first surface M1 in a direction perpendicular to the first surface M1. In the example shown in Figures 2 and 3, the fixed magnet FM2 is in contact with the variable flux magnet VM2. In other words, the fixed magnet FM2 is stacked with the variable flux magnet VM2 in a direction perpendicular to the first surface M1. Note that the fixed magnet FM2 may be spaced apart from the variable flux magnet VM2. In this case, the fixed magnet FM2 may be parallel to the variable flux magnet VM2 or non-parallel to the variable flux magnet VM2.

The magnet section MG3 includes at least a variable magnetic flux magnet VM3. The variable magnetic flux magnet VM3 is a variable magnetic flux magnet that constitutes part of the variable magnetic flux magnet VM. The variable magnetic flux magnet VM3 is also a variable magnetic flux magnet that has a thirteenth surface M13 that constitutes part of the first surface M1. In the example shown in Figures 2 and 3, the magnet section MG3 includes a fixed magnet FM3 in addition to the variable magnetic flux magnet VM3.

The variable magnetic flux magnet VM3 is a variable magnetic flux magnet with a flat, rectangular shape. Note that the shape of the variable magnetic flux magnet VM3 may be other shapes instead of a flat, rectangular shape. The variable magnetic flux magnet VM3 may be composed of multiple variable magnetic flux magnet pieces, or may be composed of a single variable magnetic flux magnet piece.

The fixed magnet FM3 may be any permanent magnet as long as its magnetic force does not change when a magnetic field is applied. In the example shown in Figures 2 and 3, the fixed magnet FM3 is a flat, rectangular magnet. In this example, the fixed magnet FM3 has a shape and size such that its outline matches (or nearly matches) the outline of the variable magnetic flux magnet VM3 in the direction perpendicular to the first surface M1, i.e., the Z-axis direction. Note that the fixed magnet FM3 may also be configured so that its outline does not match the outline of the variable magnetic flux magnet VM3 in this direction. The shape of the fixed magnet FM3 may also be other shapes instead of a flat, rectangular shape.

The fixed magnet FM3 is located on the opposite side of the variable flux magnet VM3 from the first surface M1 in a direction perpendicular to the first surface M1. In the example shown in Figures 2 and 3, the fixed magnet FM3 is in contact with the variable flux magnet VM3. That is, the fixed magnet FM3 is stacked with the variable flux magnet VM3 in a direction perpendicular to the first surface M1. Note that the fixed magnet FM3 may be spaced apart from the variable flux magnet VM3. In this case, the fixed magnet FM3 may be parallel to the variable flux magnet VM3 or non-parallel to the variable flux magnet VM3.

The magnet section MG4 includes at least a variable magnetic flux magnet VM4. The variable magnetic flux magnet VM4 is a variable magnetic flux magnet that constitutes part of the variable magnetic flux magnet VM. The variable magnetic flux magnet VM4 is also a variable magnetic flux magnet that has a fourteenth surface M14 that constitutes part of the first surface M1. In the example shown in Figures 2 and 3, the magnet section MG4 includes a fixed magnet FM4 in addition to the variable magnetic flux magnet VM4.

The variable magnetic flux magnet VM4 is a variable magnetic flux magnet with a flat, rectangular shape. Note that the shape of the variable magnetic flux magnet VM4 may be other shapes instead of a flat, rectangular shape. The variable magnetic flux magnet VM4 may be composed of multiple variable magnetic flux magnet pieces, or may be composed of a single variable magnetic flux magnet piece.

The fixed magnet FM4 may be any permanent magnet whose magnetic force does not change when a magnetic field is applied. In the example shown in Figures 2 and 3, the fixed magnet FM4 is a flat, rectangular magnet. In this example, the fixed magnet FM4 has a shape and size such that its outline matches (or nearly matches) the outline of the variable magnetic flux magnet VM4 in the direction perpendicular to the first surface M1, i.e., the Z-axis direction. Note that the fixed magnet FM4 may also be configured so that its outline does not match the outline of the variable magnetic flux magnet VM4 in this direction. The shape of the fixed magnet FM4 may also be other shapes instead of a flat, rectangular shape.

The fixed magnet FM4 is located on the opposite side of the variable flux magnet VM4 from the first surface M1 in a direction perpendicular to the first surface M1. In the example shown in Figures 2 and 3, the fixed magnet FM4 is in contact with the variable flux magnet VM4. In other words, the fixed magnet FM4 is stacked with the variable flux magnet VM4 in a direction perpendicular to the first surface M1. Note that the fixed magnet FM4 may be spaced apart from the variable flux magnet VM4. In this case, the fixed magnet FM4 may be parallel to the variable flux magnet VM4 or non-parallel to the variable flux magnet VM4.

Here, some or all of the four variable flux magnets, variable flux magnet VM1 to variable flux magnet VM4, may be variable flux magnet segments that are integrally configured, or may be variable flux magnet segments that are configured separately from one another. In the example shown in Figures 2 and 3, all four variable flux magnets are integrally configured as the variable flux magnet VM. Therefore, in this example, these four variable flux magnets are individual variable flux magnet segments of the variable flux magnet VM that is virtually divided into four variable flux magnet segments. The magnetic properties of each of these four variable flux magnets are the same as each other. However, the magnetic properties of each of these four variable flux magnets may be different from each other. In this case, the variable magnetic flux magnets VM may be configured, for example, as uneven rectangular variable magnetic flux magnets, which causes the magnetic properties of each of the four variable magnetic flux magnets to differ, or as variable magnetic flux magnets with non-uniform materials, densities, etc., which causes the magnetic properties of each of the four variable magnetic flux magnets to differ, or as other methods which cause the magnetic properties of each of the four variable magnetic flux magnets to differ.

Note that if some or all of the four variable flux magnets, variable flux magnet VM1 to variable flux magnet VM4, are configured separately from one another, the magnetic properties of two or more of these four variable flux magnets that are configured separately may be different from one another, or may be the same as one another. If the magnetic properties of the two or more variable flux magnets are different from one another, for example, at least one of the shape, thickness in a direction perpendicular to first surface M1, density, material, etc. of the two or more variable flux magnets will be different from one another. In other words, in the variable flux magnet module VMM, by making at least one of the shape, thickness, density, material, etc. of the two or more variable flux magnets different from one another, the magnetic properties of the two or more variable flux magnets can be made different from one another.

In this embodiment, the magnetic characteristics of a variable magnetic flux magnet are represented by the magnitude of the magnetic field that must be applied to the variable magnetic flux magnet to change its magnetic force to the desired magnetic force. In contrast, in this embodiment, the magnetic characteristics of a fixed magnet are represented by the magnetic force of the fixed magnet. If a fixed magnet is stacked on a variable magnetic flux magnet so that a magnetic field can be continuously applied to the variable magnetic flux magnet, the magnetic characteristics of the variable magnetic flux magnet will change depending on the magnetic field continuously applied by the fixed magnet. Therefore, even if the magnetic characteristics of the four variable magnetic flux magnets VM1 to VM4 are the same, the magnetic characteristics of the magnet sections MG1 to MG4 can be made different by varying the magnetic characteristics of the four fixed magnets FM1 to FM4. In the example shown in Figures 2 and 3, the magnetic characteristics of these four variable magnetic flux magnets were the same. Therefore, in this example, the magnetic characteristics of the four fixed magnets are different from each other. As a result, the magnetic characteristics of each of the four magnet sections are different from one another. The magnetic characteristics of each of the four magnet sections are determined by the magnetic characteristics of the variable magnetic flux magnets and fixed magnets contained in each magnet section. Therefore, the magnetic characteristics of a given magnet section are expressed by the magnitude of the magnetic field that must be applied to that magnet section in order to change the magnetic force of that magnet section to the desired magnetic force.

Note that if the magnetic properties of the four fixed magnets FM1 to FM4 are different from one another, then at least one of the following will be different: the shape of each of these four fixed magnets, the thickness in the direction perpendicular to the first surface M1, the density, the material, etc. In other words, in the variable flux magnet module VMM, by making at least one of the shape, thickness, density, material, etc. of each of these four fixed magnets different from one another, it is possible to make the magnetic properties of each of the four fixed magnets different from one another.

Furthermore, in the variable magnetic flux magnet module VMM, some or all of the four fixed magnets, FM1 to FM4, may be replaced with variable magnetic flux magnets. This also allows the magnetic properties of the four magnet sections, MG1 to MG4, in the variable magnetic flux magnet module VMM to be different from one another.

Furthermore, in the variable flux magnet module VMM, the magnet section MG1 may be configured to further include other variable flux magnets in addition to the variable flux magnet VM1 and fixed magnet FM1. Further, in the variable flux magnet module VMM, the magnet section MG2 may be configured to further include other variable flux magnets in addition to the variable flux magnet VM2 and fixed magnet FM2. Further, in the variable flux magnet module VMM, the magnet section MG3 may be configured to further include other variable flux magnets in addition to the variable flux magnet VM3 and fixed magnet FM3. Further, in the variable flux magnet module VMM, the magnet section MG4 may be configured to further include other variable flux magnets in addition to the variable flux magnet VM4 and fixed magnet FM4. By implementing some or all of these, the magnetic properties of the four magnet sections, magnet sections MG1 to MG4, in the variable flux magnet module VMM can be made different from one another.

To briefly summarize magnet unit MG, each of the four magnet units in magnet unit MG includes at least one variable magnetic flux magnet and has magnetic properties that correspond to the magnet it includes, with the magnetic properties being different from each other. Figure 4 is a diagram showing an example of the magnetic properties of each of the four magnet units included in magnet unit MG. The horizontal axis of the graph shown in Figure 4 represents the strength of the magnetic field applied to magnet unit MG. The vertical axis of the graph represents the strength of the magnetic force. The graph shown in Figure 4 shows that the magnetic properties of magnet units MG1 to MG4 are different from each other. Furthermore, the magnetic properties of magnet units MG1 to MG4 are also different from the magnetic properties of magnet unit MG when magnet unit MG includes only variable magnetic flux magnet VM (i.e., only variable magnetic flux magnets VM1 to VM4), i.e., the magnetic properties of variable magnetic flux magnet VM.

The graph shown in FIG. 4 also shows that the magnetic forces of the four magnet units can be changed in stages in the order of magnet unit MG4, magnet unit MG3, magnet unit MG2, and magnet unit MG1, depending on the magnitude of the current flowing through the magnetization coil C, which generates the magnetic field applied to magnet unit MG. For example, when a magnetic field of the strength indicated by H1 in FIG. 4 is applied to magnet unit MG, the magnetic force of magnet unit MG4 changes, but the magnetic forces of magnet units MG1 to MG3 do not change. Furthermore, when a magnetic field of the strength indicated by H2 in FIG. 4 is applied to magnet unit MG, the magnetic forces of magnet units MG3 and MG4 change, but the magnetic forces of magnet units MG1 and MG2 do not change. This allows the variable flux magnet module VMM to change the net magnetic force of magnet unit MG in three or more stages. Such a change in magnetic force over three or more stages is difficult to achieve with the variable flux magnet module X described above. By being able to change magnetic force over three or more stages, the variable flux magnet module VMM can achieve more precise field weakening in the rotating electric machine 10, and more reliably improve the efficiency of the rotating electric machine 10.

The magnetized coil C may be any coil capable of generating a magnetic field that penetrates the first surface M1. Below, as an example, we will explain a case where the magnetized coil C is a spiral coil having a coil surface that is parallel (or nearly parallel) to the first surface M1, excluding tilt due to bending, distortion, etc. Note that the magnetized coil C may also be a spiral coil having a coil surface that is not parallel to the first surface M1, or may be a type of coil other than a spiral coil. 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.

In the example shown in Figures 2 and 3, the magnetized coil C is composed of a conductor wound around the side surface of the magnet part MG. When the first surface M1 is considered to be the front, the side surface of the magnet part MG refers to the surface of the magnet part MG that faces the first surface M1 (in this example, the surface of the magnet part MG on the negative side of the Z axis) and the surface that connects the first surface (in this example, the surface of the magnet part MG that is perpendicular to the XY plane spanned by the X axis and Y axis).

The magnetized coil C may be configured to be arranged on the first surface M1 so that its coil surface overlaps with all of the 11th surface M11, 12th surface M12, 13th surface M13, and 14th surface M14 in a direction perpendicular to the first surface M1. In this case, the variable flux magnet module VMM may be configured to include multiple magnetized coils as the magnetized coil C. Some of these multiple magnetized coils are arranged on the first surface M1 so that their coil surfaces overlap with the 11th surface M11 in a direction perpendicular to the first surface M1. Other of these multiple magnetized coils are arranged on the first surface M1 so that their coil surfaces overlap with the 12th surface M12 in a direction perpendicular to the first surface M1. Still other of these multiple magnetized coils are arranged on the first surface M1 so that their coil surfaces overlap with the 13th surface M13 in a direction perpendicular to the first surface M1. Furthermore, the remaining magnetization coils are arranged on the first plane M1 so that their coil surfaces overlap the fourteenth plane M14 in a direction perpendicular to the first plane M1.

In a variable flux magnet module VMM configured as described above, when current flows through the magnetizing coil C, the magnetizing coil C generates a magnetic field that penetrates the first surface M1. In other words, in the variable flux magnet module VMM, in this case, the magnetic flux representing the magnetic field generated by the magnetizing coil C penetrates the first surface M1. Below, as an example, we will explain a case where, when a magnetic field penetrates the first surface M1 in the positive direction of the Z axis, the net magnetic force of the magnet section MG increases in accordance with the strength of the magnetic field that penetrates the first surface M1, and when a magnetic field penetrates the first surface M1 in the negative direction of the Z axis, the net magnetic force of the magnet section MG decreases in accordance with the strength of the magnetic field that penetrates the first surface M1.

<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. 5 . FIG. 5 is a diagram showing the first modified example of the configuration of the variable flux magnet module VMM. In this first modified example, each of the four magnet sections, magnet section MG1 to magnet section MG4, includes a variable flux magnet that is separate from one another, and does not include a fixed magnet. More specifically, in this modified example, magnet section MG1 includes a variable flux magnet VM1 that is separate from each of variable flux magnet VM2 to variable flux magnet VM4, and does not include a fixed magnet FM1. Also, in this modified example, magnet section MG2 includes a variable flux magnet VM2 that is separate from each of the variable flux magnet VM1, variable flux magnet VM3, and variable flux magnet VM4, and does not include a fixed magnet FM2. Also, in this modified example, magnet section MG3 includes a variable flux magnet VM3 that is separate from each of the variable flux magnet VM1, variable flux magnet VM2, and variable flux magnet VM4, and does not include a fixed magnet FM3. Furthermore, in this modified example 1, the magnet section MG4 includes a variable flux magnet VM4 that is separate from each of the variable flux magnets VM1 to VM3, and does not include a fixed magnet FM3. In this modified example 1, the magnetic properties of the variable flux magnets VM1 to VM4 are different from one another. As a result, the magnetic properties of the magnet sections MG1 to MG4 are also different from one another.

Here, Figure 6 is a diagram showing another example of the magnetic properties of each of the four magnet parts included in magnet part MG. The horizontal axis of the graph shown in Figure 6 represents the strength of the magnetic field applied to magnet part MG. The vertical axis of the graph represents the strength of the magnetic force. From the graph shown in Figure 6, it can be seen that even in Modification 1 of the embodiment, the magnetic properties of magnet parts MG1 to MG4 are different from each other. Furthermore, from the graph, it can be seen that in Modification 1 of the embodiment, the ranges of change in the magnetic force (ranges of magnetic force magnitude) of magnet parts MG1 to MG4 are different from each other.

Furthermore, the graph shown in Figure 6 shows that the magnetic forces of the four magnet parts can be changed in stages in the order of magnet part MG4, magnet part MG3, magnet part MG2, and magnet part MG1, depending on the magnitude of the current flowing through the magnetized coil C, which generates the magnetic field applied to magnet part MG. For example, when a magnetic field of the strength indicated by H3 in Figure 6 is applied to magnet part MG, the magnetic force of magnet part MG4 changes in magnet part MG, but the magnetic forces of magnet parts MG1 to MG3 do not change. Furthermore, when a magnetic field of the strength indicated by H4 in Figure 6 is applied to magnet part MG, the magnetic forces of magnet parts MG3 and MG4 change in magnet part MG, but the magnetic forces of magnet parts MG1 and MG2 do not change. In this case, the magnetic force of magnet part MG3 is different from the magnetic force of magnet part MG4. As a result, even in the first modified embodiment, the variable flux magnet module VMM can change the net magnetic force of the magnet section MG in three or more stages. Because the magnetic force can be changed in three or more stages, the variable flux magnet module VMM can achieve more precise field weakening in the rotating electric machine 10, and more reliably improve the efficiency of the rotating electric machine 10.

<Variation 2 of the configuration of the variable magnetic flux magnet module>
The following describes a second modified example of the configuration of the variable magnetic flux magnet module VMM. In this second modified example, the variable magnetic flux magnet module VMM includes a magnetic body MB in addition to the magnet section MG and the magnetizing coil 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 unmagnetized magnetic bodies and magnetized magnetic bodies such as fixed magnets FM1 to FM4. The magnetic body MB is a magnetic body that covers at least a portion of the surface of the magnet portion MG. The following describes, as an example, a case in which the magnetic body MB is a rectangular parallelepiped magnetic body having a recess CC that houses the magnet portion MG together with the magnetized coil C. Note that the magnetic body MB may be composed of multiple magnetic body pieces or a single magnetic body piece. Figure 7 is a diagram showing an example of the magnet portion MG housed together with the magnetized coil C in the recess CC of the magnetic body MB. Figure 8 is a diagram showing an example of the magnet portion MG being removed from the recess CC of the magnetic body MB shown in Figure 7. However, in Figures 7 and 8, the magnet portion MG is depicted as a simple rectangular parallelepiped object to avoid cluttering the illustration.

As shown in Figure 7, when the magnet section MG 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. 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. In other words, in this case, the variable magnetic flux magnet module VMM can reduce eddy current loss.

Note that when the variable flux magnet and the fixed magnet are spaced apart in the variable flux magnet module VMM (for example, when the variable flux magnet VM1 and the fixed magnet FM1 are spaced apart), the magnet section MG may be configured so that the spaced apart variable flux magnet and the fixed magnet are housed in separate recesses (for example, one of the two recesses is recess CC), or the spaced apart variable flux magnet and the fixed magnet are housed together in recess CC. When the spaced apart variable flux magnet and the fixed magnet are housed separately in the magnetic body MB, the magnetic body MB has recess CC and a recess separate from recess CC.

<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. 9 . FIG. 9 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. 9 is performed. The following describes, as an example, a case in which information indicating the initial value of the magnetic force of the magnet unit MG 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. 9, for example, until the rotation of the rotating electrical machine 10 is stopped.

Here, in the processing of the flowchart shown in FIG. 9, the control device 20 changes the magnetic force of the variable magnetic 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 change the magnetic force of the magnet section MG in three or more stages. In this case, the memory unit of the control device 20 stores, for example, first correspondence information in which rotation speed range information and magnetic force information indicating the magnetic force of the variable magnetic flux magnet VM are associated with each other for three or more 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 addition, in this case, the memory unit of the control device 20 stores, for example, second correspondence information in which magnetic force information and current information are associated with each other for three or more magnetic force information. The current information refers to information indicating the current flowing through the magnetized coil C (for example, a value indicating the direction of the current flowing through the magnetized coil C represented by a positive or negative sign and the magnitude of the current). Specifically, the current information associated with certain magnetic force information indicates the magnitude of the current to be passed through the magnetizing coil C in order to change the magnetic force of the magnet part MG to the magnetic force indicated by the magnetic force information.

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 S110). 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 S110 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 S120).

Next, the control device 20 identifies magnetic force information indicating the target magnetic force identified in step S120 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 current indicated by the current information associated with the identified magnetic force information as the current to be passed through the magnetized coil C (step S130). For example, if the target magnetic force is the aforementioned third magnetic force, the control device 20 identifies the third current indicated by the current information associated with the magnetic force information indicating the third magnetic force as the current to be passed through the magnetized coil C. Also, for example, if the target magnetic force is the aforementioned second magnetic force, the control device 20 identifies the second current indicated by the current information associated with the magnetic force information indicating the second magnetic force as the current to be passed through the magnetized coil C. Also, for example, if the target magnetic force is the aforementioned first magnetic force, the control device 20 identifies the first current indicated by the current information associated with the magnetic force information indicating the first magnetic force as the current to be passed through the magnetized coil C.

Next, the control device 20 passes the current determined in step S130 through the magnetized coil C to change the magnetization of the magnet section MG (step S140). By processing step S140, the control device 20 can change the magnetic force of the magnet section MG to the target magnetic force. After processing step S140, the control device 20 transitions to step S110 and again determines the rotation speed of the rotating electric machine 10.

As described above, the control device 20 can change the magnetic force of the magnet section MG in three or more stages of different magnitudes depending on the rotation speed of the rotating electric machine 10. As a result, the control device 20 can achieve field weakening for the rotating electric machine 10 and improve the efficiency of the rotating electric machine 10.

Note that some or all of the fixed magnets FM1 to FM4 described above may be configured as an integrated unit. In this case, some or all of the integrated fixed magnets FM1 to FM4 may be configured as fixed magnets having regions with continuously varying magnetic forces, or may be configured as regions with discretely varying magnetic forces.
Furthermore, the first surface M1 described above may be a flat surface or may be a surface having projections and recesses. When the first surface M1 is a surface having projections and recesses, for example, some or all of the twelfth surface M12 of the variable magnetic flux magnet VM2, the thirteenth surface M13 of the variable magnetic flux magnet VM3, and the fourteenth surface M14 of the variable magnetic flux magnet VM4 may be surfaces that are parallel to the eleventh surface M11 of the variable magnetic flux magnet VM1 in a direction perpendicular to the first surface M1, and may not be included in a virtual plane that includes the eleventh surface M11.

As described above, the variable magnetic flux magnet module according to the embodiment (in the example described above, the variable magnetic flux magnet module VMM) comprises a magnet section (in the example described above, the magnet section MG) having a first surface (in the example described above, the first surface M1) and a coil (in the example described above, the magnetizing coil C) that generates a magnetic field that penetrates the first surface, and the magnet section comprises a first variable magnetic flux magnet (in the example described above, the magnet section MG) having an eleventh surface (in the example described above, for example, the eleventh surface M11). The variable flux magnet module includes a first magnet section (for example, magnet section MG1 in the example described above) including a variable flux magnet VM1, and a second magnet section (for example, magnet section MG2 in the example described above) including a second variable flux magnet (for example, variable flux magnet VM2 in the example described above) having a twelfth surface (for example, twelfth surface M12 in the example described above), where the eleventh and twelfth surfaces constitute at least a part of the first surface, and the magnetic properties of the second magnet section differ from the magnetic properties of the first magnet section. This allows the variable flux magnet module to fine-tune the magnetic force of the magnet sections.

Furthermore, in the variable magnetic flux magnet module, the first magnet section may include a first fixed magnet (for example, fixed magnet FM1 in the example described above) along with the first variable magnetic flux magnet, and the first fixed magnet may be located on the opposite side of the first surface, sandwiching the first variable magnetic flux magnet, in a direction perpendicular to the first surface.

Furthermore, in the variable magnetic flux magnet module, the first magnet section may include a third variable magnetic flux magnet in addition to the first variable magnetic flux magnet, the third variable magnetic flux magnet being located on the opposite side of the first surface across the first variable magnetic flux magnet in a direction perpendicular to the first surface, and the magnetic properties of the third variable magnetic flux magnet being different from the magnetic properties of the first variable magnetic flux magnet.

Furthermore, in the variable magnetic flux magnet module, the second magnet section may include a second fixed magnet (for example, fixed magnet FM2 in the example described above) in addition to the second variable magnetic flux magnet, and the second fixed magnet may be located on the opposite side of the first surface, sandwiching the second variable magnetic flux magnet, in a direction perpendicular to the first surface.

Furthermore, in the variable magnetic flux magnet module, the second magnet section may include a fourth variable magnetic flux magnet in addition to the second variable magnetic flux magnet, the fourth variable magnetic flux magnet being located on the opposite side of the first surface across the second variable magnetic flux magnet in a direction perpendicular to the first surface, and the magnetic properties of the fourth variable magnetic flux magnet being different from the magnetic properties of the second variable magnetic flux magnet.

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the first magnet section includes a first fixed magnet together with a first variable magnetic flux magnet, the first fixed magnet being located on the opposite side of the first surface across the first variable magnetic flux magnet in a direction perpendicular to the first surface, the second magnet section includes a second fixed magnet together with a second variable magnetic flux magnet, the second fixed magnet being located on the opposite side of the first surface across the second variable magnetic flux magnet in a direction perpendicular to the first surface, and the magnetic properties of the second fixed magnet being different from the magnetic properties of the first fixed magnet.

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the shape of the second fixed magnet is different from the shape of the first fixed magnet.

Furthermore, the variable magnetic flux magnet module may be configured such that the thickness of the second fixed magnet in a direction perpendicular to the first surface is different from the thickness of the first fixed magnet.

Furthermore, the variable flux magnet module may be configured such that the magnetic properties of the second variable flux magnet are different from the magnetic properties of the first variable flux magnet.

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the shape of the second variable magnetic flux magnet is different from the shape of the first variable magnetic flux magnet.

Furthermore, the variable flux magnet module may be configured such that the thickness of the second variable flux magnet is different from the thickness of the first variable flux magnet in a direction perpendicular to the first surface.

Furthermore, in a variable magnetic flux magnet module, the coil may be composed of a conductor wound around the side of the magnet unit, and the side of the magnet unit may be the surface of the magnet unit that connects the first surface to the surface that faces the first surface when the first surface is the front.

Furthermore, in the variable magnetic flux magnet module, a configuration may be used in which the coil is arranged on the first surface so that the coil surface overlaps both the 11th and 12th surfaces in a direction perpendicular to the first surface.

The variable magnetic flux magnet module may also be configured to include a plurality of first coils, some of which are arranged on the first surface so that the coil surfaces overlap the 11th surface in a direction perpendicular to the first surface, and the remaining of which are arranged on the first surface so that the coil surfaces overlap the 12th surface in a direction perpendicular to the first surface.

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

Furthermore, in the variable magnetic flux magnet module, the magnetic body may be configured to cover at least a portion of the surface of the magnet section.

Furthermore, in the variable magnetic flux magnet module, the magnetic body may have a recess (recess CC in the example described above) that houses the magnet section together with the coil, and the magnet section may be housed in the recess together with the 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 the coil.

Furthermore, in the variable magnetic flux magnet module, when the control unit changes the magnetic force of the magnet unit to a target magnetic force, it may be configured to pass a current corresponding to the target magnetic force through the coil.

The variable magnetic flux magnet module may also have a magnet unit that includes a variable magnetic flux magnet, and the magnetic force of the magnet unit may be changed in three or more stages. The variable magnetic flux magnet module may also be configured to fine-tune the magnetic force of the magnet unit.

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... Magnetizing coil, M1... First surface, M11... Eleventh surface, M12... Twelfth surface, M13... Thirteenth surface, M14... Fourteenth surface, MB... Magnetic body, MG, MG1-MG4... Magnet unit, FM1-FM4... Fixed magnet, VM, VM1-VM4... Variable flux magnet, VMM, VMM-1-VMM-6... Variable flux magnet module

Claims (14)

a magnet portion having a first surface;
a coil that generates a magnetic field that penetrates the first surface;
Equipped with
the magnet unit includes a plurality of variable flux magnets having surfaces that form the first surface ,
the plurality of variable magnetic flux magnets are arranged in a matrix,
The magnetic properties of some or all of the plurality of variable magnetic flux magnets are different from each other .
Variable flux magnet module. the magnet unit includes a fixed magnet together with at least one of the plurality of variable flux magnets,
the fixed magnet is located on the opposite side of the first surface with the plurality of variable magnetic flux magnets in between in a direction perpendicular to the first surface;
The variable flux magnet module of claim 1 . the magnet unit includes a plurality of the fixed magnets,
The shapes of at least some of the plurality of fixed magnets are different from each other .
The variable flux magnet module according to claim 2 . In a direction perpendicular to the first surface, thicknesses of at least some of the plurality of fixed magnets are different from each other .
The variable flux magnet module according to claim 3 . The shapes of at least some of the plurality of variable magnetic flux magnets are different from each other .
The variable flux magnet module of claim 1 . the coil is made of a conductor wound around the side surface of the magnet portion,
When the first surface is the front surface, the side surface of the magnet part is a surface that connects the first surface and a surface that faces the first surface among the surfaces of the magnet part.
A variable flux magnet module according to any one of claims 1 to 5 . the coil is disposed on the first surface such that a coil surface overlaps with a surface of each of the plurality of variable magnetic flux magnets in a direction perpendicular to the first surface;
7. A variable flux magnet module according to any one of claims 1 to 6 . The coil includes a plurality of first coils,
some of the plurality of first coils are arranged on the first surface such that a coil surface overlaps with a surface of some of the plurality of variable magnetic flux magnets in a direction perpendicular to the first surface;
the remaining of the plurality of first coils are arranged on the first surface such that their coil surfaces overlap with surfaces of the remaining of the plurality of variable magnetic flux magnets in a direction perpendicular to the first surface;
A variable flux magnet module according to any one of claims 1 to 7 . Further comprising a magnetic material,
A variable flux magnet module according to any one of claims 1 to 8 . The magnetic body covers at least a part of the surface of the magnet portion.
The variable flux magnet module of claim 9 . the magnetic body has a recess that accommodates the magnet portion together with the coil,
The magnet portion is accommodated in the recess together with the coil.
11. The variable magnetic flux magnet module according to claim 9 or 10 . Further comprising a control unit that applies a current to the coil.
A variable flux magnet module according to any one of claims 1 to 11 . When the control unit changes the magnetic force of the magnet unit to a target magnetic force, the control unit causes a current corresponding to the target magnetic force to flow through the coil.
13. The variable flux magnet module of claim 12 . A variable flux magnet module according to any one of claims 1 to 13 ,
Rotating electric motor.