Processing device, processing method, program, and core

Abstract

A processing device (410) generates, on the basis of distribution of magnetic characteristics in a design region of an original core, distribution of a generation index of a magnetic flux inhibition part in a core to be designed, and determines, on the basis of the distribution of the generation index, a region of the magnetic flux inhibition part in the core.

Description

Processing device, processing method, program, and core

[0001] This disclosure relates to a processing device, a processing method, a program, and a core, and is particularly suitable for use in designing a core. This application claims priority to Japanese Patent Application No. 2024-018904, filed February 9, 2024, the contents of which are incorporated herein by reference in their entirety.

[0002] In devices that include a core, the design of the core can have a significant impact on the performance of the device (hereinafter, devices that include a core will also be simply referred to as devices). Some devices include cores that include magnetic flux inhibiting portions. A magnetic flux inhibiting portion is a portion where magnetic flux passes more difficultly than in other portions of the core, or a portion where magnetic flux does not pass through. Therefore, the flow of magnetic flux within and around the core changes depending on the number, position, shape, and size of the magnetic flux inhibiting portions. An example of such a magnetic flux inhibiting portion is a gap portion. Hereinafter, a magnetic flux inhibiting portion that is a gap portion will also be referred to as a flux barrier.

[0003] Techniques for designing magnetic flux obstruction parts such as flux barriers include those described in Patent Document 1 and Non-Patent Document 1. Patent Document 1 describes setting a region of the basic shape of the flux barrier within a design domain and calculating an optimal solution for mapping to be applied to the region of the basic shape. Specifically, Patent Document 1 calculates, as an optimal solution, a mapping that maximizes or minimizes the characteristic value (objective function value) of the device when the device is operated. Then, the flux barrier is generated by applying the optimal mapping to the basic shape of the flux barrier. In this way, the technology described in Patent Document 1 uses a matrix representing the mapping to be applied to the region of the basic shape of the flux barrier as a design variable, and calculates an optimal solution for the matrix.

[0004] Furthermore, Non-Patent Document 1 describes the generation of a flux barrier for an IPM motor using a method that improves on the On-Off method. The On-Off method calculates whether each of multiple meshes obtained by dividing a design domain is in an on state or an off state. For example, the on state corresponds to a magnetic material, and the off state corresponds to air. The On-Off method searches for the optimal solution for each cell (on state or off state) that minimizes or maximizes the value of the objective function within the range in which the constraints are satisfied. In a typical On-Off method, the state of each cell is calculated as being independent of the states of other cells. In contrast, Non-Patent Document 1 calculates the state of each cell based on the output of a normalized Gaussian network (NGnet) for each cell. The output of the NGnet is expressed as a weighted sum of normalized Gaussian functions whose values ​​vary smoothly spatially. In the technology described in Non-Patent Document 1, weight coefficients for the normalized Gaussian functions are used as design variables, and the optimal solution for these weight coefficients is calculated.

[0005] Japanese Patent Application Laid-Open No. 2021-114099

[0006] Takahiro Sato and five others, "Rotor Shape Optimization of Interior Permanent Magnet Synchronous Motors Using Topology Optimization," IEEJ Transactions on Industry Applications, Vol. 135, No. 3, pp. 291-298, 2015.

[0007] However, in the methods described in Patent Document 1 and Non-Patent Document 1, the ease (and difficulty) of selecting a candidate solution does not change depending on the location of the flux obstruction, as long as the location is one where a flux obstruction can exist. Therefore, in the process of searching for a solution, there is an increased possibility that a flux barrier that contributes little to improving core characteristics will be generated. This may result in a long time for the solution to converge to the optimal solution. This may increase the computational load. On the other hand, relaxing the convergence conditions to suppress the increase in computational load increases the possibility that a flux barrier that contributes little to improving core characteristics will be generated based on the optimal solution.

[0008] The present disclosure has been made in consideration of the above-mentioned problems, and aims to generate a magnetic flux obstruction portion that improves the characteristics of a core without imposing a large calculation load.

[0009] The processing device of the present disclosure is a processing device that performs processing for designing a core having a magnetic flux inhibiting portion, and is equipped with an index calculation unit that calculates a distribution of generation indices that evaluate the ease of generating the magnetic flux inhibiting portion in a design area of ​​an original core that serves as the prototype of the designed core, based on the distribution of magnetic properties in the design area, and a determination unit that determines the area of ​​the magnetic flux inhibiting portion in the design area based on the distribution of the generation indices, wherein the design area is an area on a cut surface of the original core, and the cut surface of the original core is a cut surface in a direction perpendicular to the direction in which the magnetic flux inhibiting portion is viewed in a plane.

[0010] The processing method disclosed herein is a processing method for performing processing to design a core having a magnetic flux inhibiting portion, and includes an index calculation process for calculating a distribution of generation indices that evaluate the ease of generating the magnetic flux inhibiting portion in a design area of ​​an original core that serves as the prototype of the designed core, based on the distribution of magnetic properties in the design area, and a determination process for determining the area of ​​the magnetic flux inhibiting portion in the design area based on the distribution of the generation indices, wherein the design area is an area on a cut surface of the original core, and the cut surface of the original core is a cut surface in a direction perpendicular to the direction in which the magnetic flux inhibiting portion is viewed in a plane.

[0011] The program of the present disclosure causes a computer to function as each part of the processing device.

[0012] The core of the present disclosure includes the magnetic flux obstruction portion in all or part of at least one of the regions determined by the determination portion included in the processing device.

[0013] According to the present disclosure, it is possible to generate a magnetic flux obstruction portion that improves the characteristics of a core without imposing a large computational load.

[0014] FIG. 1 is a diagram showing a first example of magnetic flux flow in a region of the rotor core where the magnetic flux density is relatively low. FIG. 2 is a diagram showing a second example of magnetic flux flow in a region of the rotor core where the magnetic flux density is relatively low. FIG. 3 is a diagram showing a first example of magnetic flux flow in a region of the rotor core where the magnetic flux density is relatively high. FIG. 4 is a diagram showing a second example of magnetic flux flow in a region of the rotor core where the magnetic flux density is relatively high. FIG. 5 is a diagram showing an example of the configuration of an IPMSM. FIG. 6 is a diagram showing an example of the functional configuration of a processing device. FIG. 7 is a flowchart explaining an example of a processing method. FIG. 8 is a diagram showing an example of sampling results. FIG. 9 is a diagram explaining an example of a method for determining a region of a magnetic flux obstruction portion. FIG. 10 is a diagram showing an example of the hardware configuration of a processing device. FIG. 11 is a diagram showing an example of a flux barrier generation result in the method of the present embodiment. FIG. 12 is a diagram showing an example of a flux barrier generation result in the method described in Patent Document 1.

[0015] An embodiment of the present disclosure will be described below with reference to the drawings. The term "sameness" in terms of length, position, size, spacing, etc., includes not only cases where the objects being compared are exactly the same, but also cases where they differ within the scope of the gist of the present disclosure (for example, differences within the tolerance range determined at the time of design). In each figure, the x-y-z coordinate system indicates the relationship between the directions in each figure. In the x-y-z coordinate system, a black circle (●) within a white circle (◯) indicates an arrow line in which the positive direction is from the back of the page to the front.

[0016] (Findings and Ideas) First, we will explain the findings and ideas that the present inventors gained when arriving at this embodiment. The techniques described in Patent Document 1 and Non-Patent Document 1 can generate flux barriers so that the characteristic values ​​(objective function values) of the device are maximized or minimized. However, for example, when performing optimization calculations, it is necessary to repeatedly search for solutions until the solutions converge to an optimal solution. Furthermore, for example, when calculating the characteristic values ​​of the device by performing electromagnetic field analysis, it is necessary to perform electromagnetic field analysis for each iteration. Therefore, increasing the number of iterations in the optimization calculation (convergence calculation) can increase the computational load. Therefore, relaxing the convergence conditions can be considered to suppress the increase in computational load. However, relaxing the convergence conditions increases the possibility that a better optimal solution will not be calculated, even if a better optimal solution actually exists. For example, it increases the possibility that a flux barrier that contributes relatively little to improving the core characteristics will be generated based on the optimal solution. Note that generating a magnetic flux obstruction portion such as a flux barrier corresponds to calculating information that can identify the area of ​​the core occupied by the magnetic flux obstruction portion. The information may be, for example, information indicating the positions (coordinates) of the boundary line between the magnetic flux obstruction portion and the outside.

[0017] 1A and 1B are diagrams illustrating the flow of magnetic flux in regions of rotor cores 101 and 102 with relatively low magnetic flux density. FIG. 1A is a diagram illustrating a case where a flux barrier 111 is present. FIG. 1B is a diagram illustrating a case where a flux barrier 111 is not present. Also, FIGS. 2A and 2B are diagrams illustrating the flow of magnetic flux in regions of rotor cores 201 and 202 with relatively high magnetic flux density. FIG. 2A is a diagram illustrating a case where a flux barrier 211 is present that extends to a region 221 on the outer circumferential surface side of rotor core 201. FIG. 2B is a diagram illustrating a case where a flux barrier that extends to a region on the outer circumferential surface side of rotor core 202 is not present (a case where a flux barrier 212 that does not extend to a region on the outer circumferential surface side of rotor core 202 is present). In FIGS. 1A, 1B, 2A, and 2B, arrows represent magnetic flux. 1A, 1B, 2A, and 2B, the denser the arrows, the higher the magnetic flux density. Although not always clear due to the notation, in FIGS. 1A, 1B, 2A, and 2B, the denser the arrows, the higher the magnetic flux density.

[0018] 1A and 1B, even if flux barrier 111 is generated in an area of ​​low magnetic flux density in rotor core 101, the magnetic flux heading toward the stator core does not change significantly. Also, little magnetic flux bypasses flux barrier 111. In other words, the motor characteristics do not change significantly with or without flux barrier 111.

[0019] 2A and 2B, in Fig. 2A, region 222 of soft magnetic material shown in Fig. 2B is replaced with region 221 of flux barrier 211. In Fig. 2A, due to the presence of region 221 of flux barrier 211 that replaces region 222 of soft magnetic material, the magnetic flux from rotor core 201 toward stator cores 231 and 232 is bent more than the magnetic flux from rotor core 202 toward stator cores 233 and 234 shown in Fig. 2B. Therefore, changing flux barrier 212 to flux barrier 211 significantly changes the characteristics of the motor.

[0020] Based on the above, the present inventors have considered that by focusing (prioritizing) calculations on core regions where the presence of flux obstructions, such as flux barriers (gaps), has a relatively large effect on motor characteristics over core regions where the effect is relatively small, it is possible to determine the regions of the flux obstructions so as to further improve core characteristics while shortening calculation time. In other words, the present inventors have considered that it is preferable to make it difficult for flux obstructions to exist in regions of the original core where the presence of flux obstructions has a relatively small effect on the characteristics of a device (e.g., a motor) (i.e., regions with relatively low magnetic flux density). Conversely, the present inventors have considered that it is preferable to make it easy for flux obstructions to exist in regions of the original core where the presence of flux obstructions has a relatively large effect on the characteristics of a device (e.g., a motor) (i.e., regions with relatively high magnetic flux density).

[0021] Here, the original core is a core that serves as the prototype of the designed core. In other words, the original core is a core that serves as a reference when designing a core with a magnetic flux obstruction portion. For example, when determining the magnetic flux obstruction portion by performing optimization calculations, the shape of the original core is used as a reference shape when evaluating the designed core, and the shape and position of the magnetic flux obstruction portion of the original core are optimized. In Figures 1A and 1B, the original core is rotor core 102 shown in Figure 1B. In Figures 2A and 2B, the original core is rotor core 202 shown in Figure 2B.

[0022] Optimization refers to, for example, searching for a solution that satisfies the conditions to be adopted as the optimal solution in an algorithm that performs optimization calculations. In this case, the solution that satisfies the conditions may be determined as the optimal solution. The original core may be modified so that the designed core has a magnetic flux inhibiting portion based on the optimal solution. Furthermore, for example, even if the conditions are not satisfied, the original core may be modified so that the designed core has a magnetic flux inhibiting portion based on a solution at an intermediate point in the optimization process.

[0023] Based on the above findings, the present inventors came up with the idea of ​​calculating the distribution of an index that determines the likelihood of generating magnetic flux obstructions in a design region of an original core based on the distribution of magnetic properties (e.g., magnetic flux density) in the design region, and determining the region of the magnetic flux obstructions based on the distribution of the generation index. Hereinafter, the design region of the original core will also be simply referred to as the design region. Furthermore, the index that determines the likelihood of generating magnetic flux obstructions in the design region will also be referred to as the generation index.

[0024] In this way, based on the distribution of magnetic properties of the original core, it is possible to quantify the core positions that facilitate the creation of magnetic flux obstructions and the positions that make it difficult to create magnetic flux obstructions. Therefore, for example, when determining the area of ​​the magnetic flux obstruction by searching for an optimal solution for the magnetic flux obstruction, it is possible to focus on the search for the positions where the characteristics of the device (e.g., motor) change significantly depending on whether or not to create the magnetic flux obstruction. Therefore, it is possible to determine the magnetic flux obstruction that improves the core characteristics without imposing a large computational load.

[0025] Here, the design region is the region to be designed for the core. The design region is also the region on the cut surface of the original core. The cut surface of the original core is a cut surface perpendicular to the direction in which the magnetic flux obstruction portion is viewed in plan. Hereinafter, such a cut surface of the original core will also be simply referred to as the cut surface of the original core. Also, viewing the magnetic flux obstruction portion in plan refers to viewing the magnetic flux obstruction portion so that the entire flow of magnetic flux can be visualized at once by magnetic flux lines, assuming that magnetic flux flows from the north pole (first pole) of a magnet installed on the core (original core) to the south pole (second pole) of the magnet. In this case, the magnetic flux may be a portion of the magnetic flux flowing from the north pole (first pole) to the south pole (second pole) (the magnetic flux within the range visible when viewing the magnetic flux obstruction portion). In this case, it is preferable to view the magnetic flux obstruction portion from a position directly facing the magnetic flux obstruction portion. For example, if the device is a radial gap type rotating electric machine, the direction in which the magnetic flux inhibiting portion is viewed in plan is parallel to the rotation axis of the rotating electric machine. Also, if the device is an axial gap type rotating electric machine, the direction in which the magnetic flux inhibiting portion is viewed in plan is perpendicular to the rotation axis of the rotating electric machine (the radial direction of the rotating electric machine). If the device is a linear motor, the direction in which the magnetic flux inhibiting portion is viewed in plan is perpendicular to the direction in which the linear motor moves (the direction of the moving magnetic field) and the normal direction to the plane that is the path of the object equipped with the linear motor. Also, if the core is a laminated core, the direction in which the magnetic flux inhibiting portion is viewed in plan is parallel to the lamination direction of the soft magnetic plate. The magnet installed in the core may be a permanent magnet or an electromagnet.

[0026] The embodiments described below are based on the above findings and ideas. In the following description, an example is given in which the aforementioned generation index is the generation probability of a magnetic flux obstruction portion. However, the generation index is not limited to the generation probability of a magnetic flux obstruction portion. For example, the generation index may be expressed by a numerical value other than the generation probability. For example, the generation index may be expressed by an integer value corresponding to the ease with which a magnetic flux obstruction portion is generated. For example, the generation index may be expressed by an integer value from 1 to 10. In this case, for example, the value of the generation index may be determined so that the smaller the value of the generation index, the more unlikely it is that a magnetic flux obstruction portion will be generated.

[0027] (Core) In the embodiment described below, a case will be exemplified in which the core having the magnetic flux inhibiting portion is a rotor core included in an interior permanent magnet synchronous motor (IPMSM). Therefore, an overview of the IPMSM will be given.

[0028] FIG. 3 illustrates an example of the configuration of an IPMSM 300. This figure illustrates a so-called V-shaped IPMSM, in which permanent magnets serving as rotor poles are arranged in a V-shape. FIG. 3 also illustrates a case in which the IPMSM 300 (rotor 310) has eight poles (note that the number of poles of the IPMSM 300 is not limited). In FIG. 3 , the area PR indicated by the double-arrowed line corresponds to one pole of the IPMSM 300. If the IPMSM 300 (rotor 310) has n poles, the IPMSM 300 has n-fold rotational symmetry with the rotation axis 0 of the IPMSM 300 as the axis of rotational symmetry. n is an integer greater than or equal to 2. In the example shown in FIG. 3 , n is 8 (n=8). FIG. 3 illustrates one of four regions obtained by dividing a cross section of the IPMSM 300 perpendicular to the rotation axis 0 into four equal parts. That is, FIG. 3 illustrates the region of the IPMSM 300 that constitutes two poles of the rotor 310. These four regions have a four-fold symmetry relationship with the rotation axis 0 of IPMSM 300 as the axis of rotational symmetry (4 = 8 poles ÷ 2). Therefore, in Fig. 3, by rotating the regions shown in Fig. 3 by 90° around the center line of IPMSM 300 as the rotation axis 0, the overall configuration of the cross section of IPMSM 300 when cut perpendicular to the rotation axis 0 of a motor such as IPMSM 300 can be obtained. Hereinafter, this cross section will also be referred to as a motor cross section. The motor cross section is an example of a cross section taken in a direction perpendicular to the direction in which the magnetic flux obstruction portion is viewed in plan.

[0029] In Fig. 3 , the IPMSM 300 includes a rotor 310 and a stator 320. The stator 320 includes a stator core 321 and a stator coil (not shown). The stator 320 generates a rotating magnetic field. Note that the stator coil included in the stator 320 is not shown in Fig. 3 . The stator coil (not shown) is installed in each slot 322 of the stator core 321 (for convenience of notation, only one slot is marked in Fig. 3 ). The winding method of the stator coil is not limited. The winding method of the stator coil may be distributed winding or concentrated winding.

[0030] The rotor 310 rotates around the rotation axis 0 of the IPMSM 300. Therefore, the rotation axis 0 of the rotor 310 coincides with the rotation axis 0 of the IPMSM 300. The rotor 310 includes a rotor core 311 and multiple permanent magnets per pole. Note that FIG. 3 illustrates an example in which the number of permanent magnets per pole is two (see permanent magnets 312a to 312b). However, the number of permanent magnets per pole is not limited. The rotor core 311 is made of a soft magnetic material. The rotor core 311 is made, for example, by laminating multiple electromagnetic steel sheets.

[0031] As described above, FIG. 3 illustrates a case where multiple permanent magnets 312a to 312b are installed in rotor core 311 per pole. Therefore, multiple magnet holes are formed in rotor core 311 per pole along a direction parallel to the rotation axis 0 of rotor core 311. Hereinafter, the direction parallel to the rotation axis 0 of rotor core 311 is also referred to as the z-axis direction. The magnet holes are through-holes that penetrate in the z-axis direction. Multiple permanent magnets 312a to 312b are installed (embedded) in rotor core 311 by being inserted into the magnet holes formed in rotor core 311. As described above, FIG. 3 illustrates a region of IPMSM 300 that constitutes two poles of rotor 310. FIG. 3 illustrates a case where two permanent magnets 312a to 312b are embedded per pole. Therefore, FIG. 3 illustrates a case where a total of 16 permanent magnets are embedded in rotor core 311. In FIG. 3, for convenience of notation, only the portion constituting one pole of the rotor 310 is labeled with a reference numeral, and the reference numerals for the portions constituting the other seven poles of the rotor 310 are omitted.

[0032] In the magnet holes formed in the rotor core 311, the spaces where the permanent magnets 312a to 312b are not present become flux barriers 313a to 313d. The flux barriers 313a to 313d are regions where magnetic flux does not pass, or regions where magnetic flux passes more difficultly than the regions around the flux barriers 313a to 313d. Here, a case where no tangible material exists in the flux barriers 313a to 313d is illustrated (i.e., a case where the flux barriers 313a to 313d are voids (air regions) is illustrated). However, the magnetic flux obstruction portion is not limited to a flux barrier (void portion). For example, a non-magnetic material may be installed in the flux barriers 313a to 313d, which are voids. In this case, the non-magnetic material portion (non-magnetic material region) is included in the magnetic flux obstruction portion. When a non-magnetic material is installed in a partial region of one flux barrier, the one flux barrier includes both a non-magnetic material portion and a void portion. In this case, the non-magnetic material portion and the void portion are magnetic flux obstruction portions. The non-magnetic material portion and the void portion may be treated as a single magnetic flux obstruction portion or as separate magnetic flux obstruction portions. The magnetic flux obstruction portion may be a portion that can obstruct the flow of magnetic flux more than other portions, such as a portion where the thickness of the steel plate is made thinner by pressing, in addition to the void portion. The IPMSM itself may be a known IPMSM and is not limited to the IPMSM 300 illustrated in FIG. 3 .

[0033] Furthermore, the core having the magnetic flux inhibiting portion is not limited to the rotor core of an IPMSM. For example, the core having the magnetic flux inhibiting portion may be a rotor core of a motor other than an IPMSM. For example, the permanent magnet does not need to be embedded in the rotor core. For example, the core having the magnetic flux inhibiting portion may be a stator core. In this way, the core having the magnetic flux inhibiting portion may be at least one of the rotor core and the stator core of a rotating electric machine. The rotating electric machine may be a motor or a generator. The rotating electric machine may be a radial gap type rotating electric machine or an axial gap type rotating electric machine. In a radial gap type rotating electric machine, the rotor and the stator face each other in the radial direction of the rotating electric machine. In an axial gap type rotating electric machine, the rotor and the stator face each other in a direction parallel to the rotation axis of the rotating electric machine. Furthermore, the core having the magnetic flux inhibiting portion may be a core included in a device other than a rotating electric machine. The device other than a rotating electric machine may be, for example, a linear motor.

[0034] Furthermore, in this embodiment, the magnetic flux obstruction portion is exemplified as a flux barrier (gap portion). However, the magnetic flux obstruction portion is not limited to a flux barrier (gap portion). For example, as described above, a non-magnetic material may be provided in the flux barriers 313a to 313d. That is, the magnetic flux obstruction portion may be a non-magnetic material provided in a hollow portion of the core. In this manner, the magnetic flux obstruction portion may be a non-magnetic portion of the core. The non-magnetic portion is, for example, a region occupied by at least one of air and a non-magnetic material. Furthermore, the magnetic flux obstruction portion may be, for example, a region in a soft magnetic material where compressive residual stress is imparted. For example, when a core is formed by bonding multiple soft magnetic plates with an adhesive, adhesive is applied to the plate surfaces of the soft magnetic plates. Compressive residual stress is imparted to the region directly below the region where the adhesive is applied and to the surrounding area. Furthermore, when multiple soft magnetic plates are joined by caulking, compressive residual stress is imparted to the region where the caulking is performed and the surrounding area. These regions may be magnetic flux obstructions.

[0035] As described above, the magnetic flux inhibiting portion may be formed, for example, by making a portion of the core (a portion of the soft magnetic material) a non-magnetic region. The non-magnetic region is, for example, a region occupied by at least one of air and a non-magnetic material. The magnetic flux inhibiting portion may also be formed, for example, by imparting residual stress to a portion of the core (a portion of the soft magnetic material).

[0036] (Processing Device and Processing Method) FIG. 4 is a diagram illustrating an example of the functional configuration of the processing device 410. FIG. 5 is a flowchart illustrating an example of a processing method performed using the processing device 410. The processing device 410 includes, as hardware, one or more hardware processors and one or more memories. The processing device 410 executes various calculations by using one or more hardware processors to execute one or more programs stored in the memory. The hardware processor may be, for example, a central processing unit (CPU) or a graphics processing unit (GPU). The processing device 410 may also include a CPU and a GPU. The memory may be, for example, a random access memory (RAM) or a read-only memory (ROM). The processing device 410 may also include a RAM and a ROM. The processing device 410 may also include a storage medium other than a RAM and a ROM. The processing device 410 may also be implemented by dedicated hardware such as an application-specific integrated circuit (ASIC).

[0037] The input processing device 420 is a device for inputting various types of information to the processing device 410. For example, the input processing device 420 may include a user interface. In this case, the input processing device 420 includes, for example, a keyboard and a mouse. Furthermore, the input processing device 420 may include an information processing device (computer) separate from the processing device 410. The number of input processing devices 420 may be one, or two or more. Furthermore, at least one of the input processing devices 420 may be a device inside the processing device 410.

[0038] The output processing device 430 is a device that performs processing based on information output from the processing device 410. For example, the output processing device 430 may include a computer display. The output processing device 430 may also include an information processing device (computer) separate from the processing device 410. The output processing device 430 may also be a device used in manufacturing cores. The number of output processing devices 430 may be one or two or more. At least one of the output processing devices 430 may also be a device inside the processing device 410. Communication between the input processing device 420 and the output processing device 430 and the processing device 410 may be wired communication or wireless communication.

[0039] Next, an example of processing performed by the processing device 410 will be described. In this embodiment, a case where the processing device 410 performs processing for designing a rotor core equipped with a flux barrier is illustrated. In FIG. 4 , this embodiment illustrates a case where the processing device 410 includes an acquisition unit 411, a distribution calculation unit 412, an index calculation unit 413, a determination unit 414, and an output unit 415.

[0040] <Acquisition Unit 411, Steps S501 and S504> The acquisition unit 411 acquires premise information PI (steps S501 and S504). The premise information PI is information indicating prerequisites for the processing device 410 to generate a magnetic flux obstruction portion (a flux barrier in this embodiment). In other words, the premise information PI is information that must be set in the processing device 410 in advance in order for the processing device 410 to generate a magnetic flux obstruction portion. The content of the premise information PI is determined, for example, by a designer of the device (an IPMSM in this embodiment). In the following description, the designer of the device is also simply referred to as the designer. Note that in the following description, the designer may be substituted for the operator of the processing device 410. The premise information PI includes, for example, operating condition information, configuration condition information, analysis condition information, and region condition information. In this embodiment, the acquisition unit 411 acquires the operating condition information, configuration condition information, and analysis condition information in step S501, and acquires the region condition information in step S504.

[0041] The operating condition information is information indicating conditions related to the operation of the equipment to be designed. As described above, in this embodiment, the equipment is an IPMSM. In this case, the operating condition information includes, for example, the amplitude of the stator current (excitation current), the advance angle of the IPMSM, and the rotation speed of the IPMSM. In addition, in this embodiment, the processing device 410 performs an electromagnetic field analysis. The acquisition unit 411 sets conditions related to the operation of the equipment when performing the electromagnetic field analysis based on the operating condition information. Note that the setting of the acquisition unit 411 is realized, for example, by storing the information to be set in a storage medium.

[0042] The configuration condition information is information for specifying conditions related to the configuration of a device that includes an original core. The configuration condition information includes, for example, the number, position, size, shape, and material (such as physical properties) of component parts. In this embodiment, the component parts include, for example, a rotor core, permanent magnets, a stator core, and a stator coil. A specific example of the original core is the rotor core 311 shown in FIG. 3. As described above, FIG. 3 illustrates an example in which the rotor core 311 includes flux barriers 313a to 313d. In this way, the original core may include a magnetic flux obstruction portion. However, the original core does not necessarily have to include a magnetic flux obstruction portion.

[0043] This embodiment illustrates a case where the cross-sectional configuration of the motor in the IPMSM does not change in the height direction (z-axis direction). Therefore, this embodiment illustrates a case where two-dimensional analysis of the motor cross section is performed as the electromagnetic field analysis. Therefore, the configuration condition information includes, for example, information indicating the area (coordinate range) occupied by each component of the IPMSM on a coordinate plane. However, three-dimensional analysis including the height direction (z-axis direction) may be performed as the electromagnetic field analysis. In this case, the configuration condition information includes, for example, information indicating the area (coordinate range) occupied by each component of the IPMSM in a coordinate space. This embodiment illustrates a case where the area where the electromagnetic field analysis is performed is the design area. The design area is the area to be designed for the core. Specifically, this embodiment illustrates a case where the design area is the cross-sectional area of ​​the motor of the IPMSM 300. The design area may be, for example, the entire cross-section of the motor of the IPMSM 300. However, as described above, this embodiment illustrates a case where the IPMSM 300 has rotational symmetry. Therefore, the design area does not have to be the entire area of ​​the IPMSM 300, as long as it is, for example, an area of ​​the IPMSM 300 that includes an area that configures one pole of the rotor 310. The acquisition unit 411 sets the design area based on the configuration condition information.

[0044] The analysis condition information is information related to the conditions for electromagnetic field analysis. The analysis condition information includes, for example, information on the position, size, and shape of a minute region (mesh). The minute region (mesh) is set, for example, within an area including the IPMSM area set on a coordinate plane (or coordinate space). The acquisition unit 411 sets a mesh for the design area based on the analysis condition information. Furthermore, the acquisition unit 411 sets, for each mesh, the physical property values ​​of the area corresponding to the mesh based on the configuration condition information.

[0045] The region condition information indicates conditions for a region in which a magnetic flux obstruction portion (flux barrier in this embodiment) is to be generated. The region condition information may be information capable of identifying a region in which the generation of a magnetic flux obstruction portion is permitted. The region condition information may include information indicating a region in which the generation of a magnetic flux obstruction portion is permitted. For example, the region condition information may include coordinates of the original core in which the generation of a magnetic flux obstruction portion is permitted. The region condition information may also include information indicating a region in which the generation of a magnetic flux obstruction portion is prohibited (hereinafter, a region in which the generation of a magnetic flux obstruction portion is prohibited is also referred to as a prohibited region). In this case, a region in the region occupied by the original core other than the prohibited region is identified as a region in which the generation of a magnetic flux obstruction portion is permitted (hereinafter, a region in which the generation of a magnetic flux obstruction portion is permitted is also referred to as a permitted region). For example, the region condition information may include coordinates of a prohibited region among the coordinates of the original core. The prohibited region can be identified by the configuration condition information. The prohibited region is, for example, a region occupied by a permanent magnet. Therefore, such a region does not need to be identified by the region condition information.

[0046] In this embodiment, the distribution of magnetic properties of the original core is calculated by the distribution calculation unit 412 (described later), and information for identifying the distribution of magnetic properties is output by the output unit 415 (described later) (see also steps S502 and S503). Therefore, in this embodiment, a case where a designer determines the region condition information by referring to the distribution of magnetic properties of the original core is illustrated. Therefore, in this embodiment, a case where the acquisition unit 411 acquires the region condition information and sets the permitted region based on the region condition information in step S504 is illustrated. However, this is not necessarily required. For example, the designer may determine the region condition information without referring to the distribution of magnetic properties of the original core. For example, the region condition information may be information indicating that a region of the original core where the representative value of magnetic flux density in one period is equal to or less than a threshold value is set as the permitted region. In this case, the acquisition unit 411 may acquire the region condition information in step S501, for example. Note that the period here refers to a time period. Furthermore, the representative value may be, for example, a time average value, an effective value, or a maximum value of the absolute value of the instantaneous value.

[0047] The area condition information can prevent magnetic flux obstructions from being generated in locations where the contribution to the core and device characteristics is clearly small. For example, it can prevent magnetic flux obstructions from being generated near the inner circumferential surface 314 of the rotor core 311. This can further reduce the calculation load.

[0048] As described above, this embodiment illustrates a case where the acquisition unit 411 acquires the region condition information. However, the acquisition unit 411 does not need to acquire the region condition information. For example, if the magnetic flux obstruction portion can be located in any region of the original core as long as the magnetic flux obstruction portion can occupy that region, the acquisition unit 411 does not need to acquire the region condition information.

[0049] Furthermore, the timing at which the acquisition unit 411 acquires each piece of premise information PI (operating condition information, configuration condition information, analysis condition information, and area condition information) may be different or the same.

[0050] In this embodiment, the input processing device 420 is illustrated as having a user interface. In this case, the designer operates the input processing device 420 to input premise information PI to the input processing device 420. However, as described above, the input processing device 420 is not limited to a device having a user interface.

[0051] <Distribution Calculation Unit 412, Output Unit 415, Steps S502-S503> The distribution calculation unit 412 calculates the distribution of magnetic properties in the original core based on the results of the electromagnetic field analysis of the design region (Step S502). As described above, the design region is the region of the cross section of the original core (specifically, the motor cross section). If the design region is the region of the motor cross section of the IPMSM 300 that constitutes one pole of the rotor 310, the distribution of magnetic properties in one pole can be obtained by rotating the IPMSM 300 rotation axis 0 (rotor 310) by 360 / n degrees. As described above, n is the number of poles in the IPMSM 300 (rotor 310).

[0052] If the acquisition unit 411 acquires the area condition information before the start of the processing in step S502, the distribution calculation unit 412 calculates the distribution of the magnetic properties in an area of ​​the design area that includes the allowed area specified by the area condition information. The distribution calculation unit 412 may calculate the distribution of the magnetic properties only in the allowed area of ​​the design area, or may calculate the distribution of the magnetic properties in the entire design area.

[0053] The magnetic characteristic is, for example, a physical quantity obtained from a magnetization curve. Specifically, the magnetic characteristic may be any one of magnetic flux density, magnetic field strength, and magnetic permeability. The value of the magnetic characteristic may also be a representative value in one period. Here, the period is a time period. The representative value may also be, for example, a time average value of the absolute value of the instantaneous value, an effective value, or a maximum value. The magnetic characteristic may also be, for example, iron loss.

[0054] In this embodiment, the magnetic property is a time average value of the absolute value of the instantaneous value of the magnetic flux density. In the following description, the time average value of the absolute value of the instantaneous value of the magnetic flux density will be abbreviated as the time average value of the magnetic flux density as necessary.

[0055] For example, if the original core is the rotor core 311 shown in FIG. 3 , the distribution calculation unit 412 performs electromagnetic field analysis based on the premise information PI to calculate instantaneous values ​​of magnetic flux density and magnetic field strength at each position in the design domain of the IPMSM 300 when the IPMSM 300 shown in FIG. 3 is excited. In this embodiment, to illustrate a case where the distribution calculation unit 412 performs electromagnetic field analysis (numerical calculation), a case where each position is represented by a discretized position is illustrated. Specifically, each position is represented by, for example, the position of a representative point of a mesh (e.g., a position arbitrarily determined in advance, such as a vertex position or a center position). However, each of the above positions may be representative positions of two or more predetermined meshes.

[0056] The electromagnetic field analysis is performed by solving Maxwell's equations using a known numerical calculation method such as the finite element method. When the electromagnetic field analysis is performed using the finite element method, for example, the instantaneous values ​​of the magnetic flux density and the magnetic field strength are calculated as the instantaneous values ​​at the positions of the representative points of each mesh. The distribution calculation unit 412 can calculate the time average values ​​of the magnetic characteristics over one period by calculating the instantaneous values ​​of the magnetic flux density and the magnetic field strength over one period. The electromagnetic field analysis method itself is a common method, so a detailed description thereof will be omitted here.

[0057] As described above, in this embodiment, the designer sets the region condition information by referring to the distribution of magnetic properties in the original core. Therefore, the output unit 415 outputs information specifying the distribution of magnetic properties in the original core (in this embodiment, the distribution of the time-averaged values ​​of magnetic flux density) (step S503). Hereinafter, the information specifying the distribution of magnetic properties in the original core is also referred to as magnetic distribution information MP.

[0058] In this embodiment, the output unit 415 outputs the magnetic distribution information MP to the output processing device 430. In addition, in this embodiment, the output processing device 430 includes a computer display. In this case, the magnetic distribution information MP output from the output unit 415 is displayed on the computer display. However, as described above, the output processing device 430 is not limited to a device including a computer display.

[0059] The designer determines the permission area by referring to the magnetic distribution information MP output by the output unit 415. In this case, the acquisition unit 411 acquires area condition information for specifying the permission area determined by the designer (step S504).

[0060] As described above, this embodiment illustrates a case in which the distribution calculation unit 412 calculates the distribution of magnetic properties of the original core. However, it is not necessary for the processing device 410 (distribution calculation unit 412) to calculate the distribution of magnetic properties of the original core. For example, if there is a known distribution of magnetic properties of the original core, the processing device 410 (acquisition unit 411) may acquire information indicating the known distribution. In this case, the process of step S502 (calculation of the distribution of magnetic properties) may not be performed. Instead, for example, before the process of step S505 begins, the acquisition unit 411 performs a process of acquiring known information as magnetic distribution information MP.

[0061] As described above, the acquisition unit 411 does not need to acquire the area condition information. That is, the process of step S504 does not need to be performed. If the process of step S504 is not performed, the process of step S503 (output of the magnetic distribution information MP) does not need to be performed.

[0062] <Index Calculation Unit 413, Step S505> The index calculation unit 413 calculates a distribution of generation indices indicating the likelihood of generating a magnetic flux obstruction portion in the design region based on the distribution of magnetic properties in the design region (step S505). The distribution of generation indices may be a distribution that can identify the likelihood of each position of the core to be designed becoming a magnetic flux obstruction portion. As described above, in this embodiment, a case where such a generation indices is a distribution of the generation probability of a magnetic flux obstruction portion in the design region is illustrated. Hereinafter, the distribution of the generation probability of a magnetic flux obstruction portion in the design region is simply referred to as the generation probability distribution. The generation probability distribution may be a distribution that can identify the probability of each position of the core to be designed becoming a magnetic flux obstruction portion. The generation probability distribution may be a continuous probability distribution, a discrete probability distribution, or a probability density function. In this embodiment, a case where the index calculation unit 413 calculates a probability density function as the generation probability distribution based on the magnetic distribution information MP is illustrated. Preferably, the core to be designed and the original core differ only in the magnetic flux obstruction portion (flux barrier in this embodiment).

[0063] As explained in the "Findings and Ideas" section, it is preferable to make it easier for magnetic flux obstructions (flux barriers (gaps) in this embodiment) to exist in positions of high magnetic flux density in the original core. It is also preferable to make it harder for magnetic flux obstructions to exist in positions of low magnetic flux density in the original core. Therefore, the index calculation unit 413 may calculate the distribution of the probability of magnetic flux obstruction occurrence so that there is a positive correlation between the probability of magnetic flux obstruction occurrence and the magnetic flux density of the original core (the time-averaged value of magnetic flux density in this embodiment). That is, the probability of magnetic flux obstruction occurrence at a certain position may be higher as the magnetic flux density at that position of the original core is higher. For example, the probability of magnetic flux obstruction occurrence at each position in the core to be designed may be proportional to the magnetic flux density at that position of the original core, or may be proportional to the square of the magnetic flux density at that position.

[0064] Note that the probability of generating a magnetic flux obstruction portion does not necessarily have to be positively correlated with the magnetic flux density of the original core (the time-averaged value of the magnetic flux density in this embodiment) at all positions in the design domain of the core to be designed (e.g., the positions of all mesh representative points). For example, the index calculation unit 413 may uniformly set the generation probability of a magnetic flux obstruction portion at positions where the magnetic flux density of the original core (the time-averaged value of the magnetic flux density in this embodiment) is equal to or less than a first threshold to a predetermined value (e.g., 0%) that is lower than other generation probabilities set for positions where the magnetic flux density exceeds the first threshold. Furthermore, for example, the index calculation unit 413 may uniformly set the generation probability of a magnetic flux obstruction portion at positions where the magnetic flux density exceeds a second threshold to a predetermined value (e.g., 90%) that is higher than other generation probabilities set for positions where the magnetic flux density is equal to or less than the second threshold and is lower than 100%. A combination of these may also be used, in which case the first threshold is equal to or less than the second threshold. As described above, the index calculation unit 413 may calculate the distribution of the probability of magnetic flux obstruction portions so that, for at least a portion of the distribution, there is a positive correlation between the probability of magnetic flux obstruction portions and the magnetic flux density of the original core. Alternatively, the index calculation unit 413 may calculate the distribution of the probability of magnetic flux obstruction portions so that, for the entire distribution, there is a positive correlation between the probability of magnetic flux obstruction portions and the magnetic flux density of the original core. The location where the probability of magnetic flux obstruction portions is calculated does not have to coincide with the location where the electromagnetic field analysis is performed. In this case, for example, the probability of magnetic flux obstruction portions may be calculated for a predetermined number of adjacent meshes among the meshes set in the design area for the electromagnetic field analysis. The predetermined number may be individually set depending on the location in the design area. In the following description, information that can identify the distribution of the probability of magnetic flux obstruction portions calculated by the index calculation unit 413 in the above manner is also referred to as probability distribution information GP.

[0065] <Determination Unit 414, Output Unit 415, Steps S505 to S506> The determination unit 414 determines the area of ​​the magnetic flux inhibition portion in the design region based on the distribution of the generation probability (step S505). Hereinafter, the area of ​​the magnetic flux inhibition portion in the design region will also be simply referred to as the area of ​​the magnetic flux inhibition portion. The information on the area of ​​the magnetic flux inhibition portion determined by the determination unit 414 may be information that can identify the area of ​​the core occupied by the magnetic flux inhibition portion (flux barrier in this embodiment). The number of areas of the magnetic flux inhibition portion determined by the determination unit 414 may be one or more. If an allowed region is set, the determination unit 414 determines the area of ​​the magnetic flux inhibition portion within the allowed region. That is, the determination unit 414 determines the area of ​​the magnetic flux inhibition portion so that the entire area of ​​the magnetic flux inhibition portion is included within the allowed region. In other words, if at least a portion of the area of ​​the magnetic flux inhibition portion is outside the allowed region, the determination unit 414 does not determine the area of ​​the magnetic flux inhibition portion as the area of ​​the magnetic flux inhibition portion. However, for example, the determination unit 414 may determine the area of ​​the magnetic flux obstruction part excluding the area outside the permitted area as the area of ​​the magnetic flux obstruction part.

[0066] The determination unit 414 samples points within the design region (e.g., positions of representative points of the mesh) based on, for example, the distribution of the generation probability. The sampling method is preferably a method that makes it easier to sample locations with a high generation probability. As described above, the distribution of the generation probability is calculated so that there is a positive correlation between the generation probability of the magnetic flux obstruction portion and the magnetic flux density of the original core (in this embodiment, the time-averaged value of the magnetic flux density). Therefore, by making it easier to sample locations with a high generation probability, it becomes easier to sample locations with a high magnetic flux density of the original core. Furthermore, it becomes harder to sample locations with a low magnetic flux density of the original core. Sampling may be performed, for example, using the Markov chain Monte Carlo method or rejection sampling. For example, the distribution to be sampled may be the distribution of the generation probability itself, or a distribution based on the distribution of the generation probability. Note that the Markov chain Monte Carlo method and rejection sampling are common methods, and therefore detailed description thereof will be omitted here. Furthermore, sampling methods other than the Markov chain Monte Carlo method and rejection sampling may also be used. In this embodiment, a case will be illustrated in which the determining unit 414 samples positions within the core to be designed from the distribution of generation probabilities using the Markov Chain Monte Carlo method.

[0067] FIG. 6 shows an example of the results of sampling in an area that constitutes one pole of the rotor core. The original core has the same configuration as rotor core 311 shown in FIG. 3. In FIG. 6, the denser the area, the greater the number of samples per unit area. As shown in FIG. 6, it can be seen that more samples are taken at positions on the outer periphery of the rotor core (positions near the area where permanent magnets 312a to 323b are installed).

[0068] The determination unit 414 may select all or part of the sampled points (positions) as the region of the magnetic flux inhibiting portion. Furthermore, when the determination unit 414 samples multiple adjacent points, the determination unit 414 may select the multiple points as a single region of the magnetic flux inhibiting portion. Furthermore, the determination unit 414 may select a region of the magnetic flux inhibiting portion having a predetermined shape and size so as to include the sampled points. In this case, the determination unit 414 may select a region of the magnetic flux inhibiting portion having a predetermined shape and size as the region of the magnetic flux inhibiting portion having the sampled points as its representative point. The position of the representative point is, for example, the center of gravity (or centroid) of the magnetic flux inhibiting portion. When an allowed region is set, the determination unit 414 may sample only positions within the allowed region, or may sample the entire design region. When the entire design region is sampled, the determination unit 414 may, for example, discard magnetic flux inhibiting portions that include regions that are not allowed regions. Furthermore, for example, if a part of the magnetic flux inhibiting portion includes an area that is not an allowed area, the determiner 414 may select an area excluding the part of the magnetic flux inhibiting portion. In this embodiment, the area selected as the magnetic flux inhibiting portion in this manner is an example of a selected area selected from the design area.

[0069] The determination unit 414 may determine the region selected as described above as the region of the magnetic flux obstruction portion. However, in this embodiment, a case is illustrated in which the determination unit 414 determines the region of the magnetic flux obstruction portion as follows based on the probability distribution information GP so as to further improve the characteristics of the core and device (in this embodiment, the rotor core and IPMSM) to be designed. Figure 7 is a diagram illustrating an example of a method for determining the region of the magnetic flux obstruction portion. Figure 7 illustrates a case in which the original core 711 is the rotor core 311 shown in Figure 3.

[0070] First, the determination unit 414 selects an area including the sampled points based on the probability distribution information GP from the design area of ​​the original core 711. Then, the determination unit 414 generates an evaluation core 721 that includes a magnetic flux obstruction portion (in this embodiment, a flux barrier) in the selected area.

[0071] The determination unit 414 then calculates the characteristic values ​​of the device including the evaluation core 721 and determines the area of ​​the magnetic flux obstruction portion in the design area based on the calculated characteristic values. In this embodiment, an example is shown in which the determination unit 414 performs an electromagnetic field analysis on the evaluation core 721 to calculate the characteristic values ​​of the device including the evaluation core 721. In this case, the determination unit 414 determines the area of ​​the magnetic flux obstruction portion based on the results of the electromagnetic field analysis. Note that the characteristic values ​​of the device may be, for example, values ​​that indicate the characteristics of the device. The characteristics of the device may also be, for example, characteristics that indicate the performance of the device.

[0072] To explain a specific example of the processing of the determination unit 414 when performing electromagnetic field analysis on the evaluation core 721, first, the determination unit 414 selects a candidate region for the magnetic flux obstruction portion so that the sampled point becomes the representative point based on the probability distribution information GP. As described above, the position of the representative point is, for example, the center of gravity (or centroid) of the magnetic flux obstruction portion. If an allowed region is set as described above, the determination unit 414 may sample only positions within the allowed region, or may sample the entire design region.

[0073] For example, the determination unit 414 may determine the region of the magnetic flux obstruction portion using a method improved from the method described in Patent Document 1. In the method described in Patent Document 1, a region of the basic shape of the flux barrier is set within the design region. For example, the determination unit 414 may set a circular region as the region of the basic shape of the flux barrier in the region of the design region of the original core 711 shown in FIG. 7 , other than the permanent magnets 713aa to 713e and the flux barriers 712a to 712h. The region may be one or more. The basic shape may also be a shape other than a circle. The region of the flux barriers 712a to 712h shown in FIG. 7 may also be the region of the basic shape of the flux barrier. The determination unit 414 then calculates an optimal solution for mapping the region of the basic shape of the flux barrier using an optimization algorithm. In this case, the determination unit 414 uses a characteristic value of the device, such as the average torque of the rotor, as the value of the objective function.

[0074] When calculating an optimal solution for mapping the region of the basic shape of the flux barrier using metaheuristics such as a genetic algorithm, the determination unit 414 calculates candidate solutions for the mapping. Hereinafter, the optimal solution and candidate solutions for mapping the region of the basic shape of the flux barrier are simply referred to as the optimal solution and the candidate solution, respectively. The determination unit 414 generates a flux barrier by applying the mapping represented by the candidate solution to the region of the basic shape of the flux barrier. The number of flux barriers may be one or more. If there are multiple flux barriers, there may be multiple candidate solutions. In this case, the determination unit 414 may select candidate solutions corresponding to each of the multiple flux barriers. Furthermore, in this case, the determination unit 414 may apply the mapping represented by the candidate solution corresponding to the flux barrier to the region of the basic shape of the flux barrier.

[0075] For example, in Figure 7, the determination unit 414 sets the region of flux barriers 712a to 712h within the region of original core 711 as the region of the basic shape of the flux barrier. The determination unit 414 generates evaluation core 721 by applying a mapping represented by the candidate solution to the basic shape of the flux barrier. Figure 7 illustrates an example in which flux barriers 712a to 722g and 732a to 732e are generated as a result of this mapping. In this case, the regions of flux barriers 722a to 722e and 732a to 732e are examples of selected regions.

[0076] The determination unit 414 generates an evaluation core including one or more flux barriers that have been mapped as described above. In FIG. 7 , the determination unit 414 generates evaluation cores 721 and 731. The determination unit 414 then calculates the characteristic values ​​of the IPMSM including the evaluation core 721 to calculate the value of the objective function. The determination unit 414 updates candidate solutions according to an optimization algorithm such as a genetic algorithm based on the calculated objective function value. The optimization algorithm may be a metaheuristic or another algorithm. The optimal solution is calculated by repeatedly updating the candidate solutions in this manner until a convergence condition is satisfied. The determination unit 414 determines the flux barrier area by applying the mapping represented by the optimal solution to the area of ​​the basic shape of the flux barrier in the design area of ​​the original core 711.

[0077] 7 illustrates an example in which flux barriers 732a to 732e are generated by applying a mapping represented by the optimal solution to the region of flux barriers 712a to 712h (the region of the basic shape of the flux barriers) in the design region of original core 711. In this case, flux barriers 722a to 722e are generated by applying a mapping represented by a candidate solution other than the optimal solution to the region of flux barriers 712a to 712h.

[0078] As described above, calculating an optimal solution by solving an optimal solution problem is preferable because it allows for the design of a core that exhibits better values ​​for the device characteristic values. However, the determination unit 414 does not necessarily have to solve the optimal solution problem. For example, the designer may vary the design variables through trial and error. In this case, the determination unit 414 may search for design variables whose device characteristic values ​​satisfy a predetermined condition from among the design variables specified by the designer. The predetermined condition may be, for example, that the device characteristic value is better than a predetermined value.

[0079] For example, in the method described in Patent Document 1, the determination unit 414 may calculate an initial candidate solution so that the position of the representative point of the flux barrier when mapped onto the area of ​​the basic shape of the flux barrier is the position of the point sampled as described above.

[0080] Furthermore, when updating a candidate solution, the determination unit 414 may calculate the updated candidate solution such that the position of the representative point of the flux barrier when mapping represented by the updated candidate solution is performed becomes the position of the point sampled as described above. The determination unit 414 may calculate both the initial candidate solution and the updated candidate solution in the above manner, or may calculate only one of them in the above manner.

[0081] By doing this, according to the distribution of generation probability, the greater the influence a position has on the characteristics of the core and the equipment, the more likely it is to be calculated as a representative point of the flux barrier. Conversely, the smaller the influence a position has on the characteristics of the core and the equipment, the more difficult it is to calculate as a representative point of the flux barrier. Therefore, it is possible to reduce the calculation load while increasing the probability that a sampled point is included in a magnetic flux obstruction portion.

[0082] In the method described in Patent Literature 1, for example, the shape of the flux barrier is changed by applying a mapping to the shape of the basic region of the flux barrier. Furthermore, in the method described in Patent Literature 1, for example, as a result of applying a mapping to the region of the basic shape of the flux barrier, one flux barrier may be separated into multiple flux barriers. In such cases, the number of flux barriers increases, so a flux barrier is added. On the other hand, multiple flux barriers may be combined into one flux barrier. In such cases, the number of flux barriers is reduced. Furthermore, in the method described in Patent Literature 1, the flux barrier may or may not be present in the original core. If a flux barrier does not exist in the original core, for example, a region of the basic shape of the flux barrier is added to add a flux barrier to the original core. Furthermore, if a flux barrier exists in the original core, the region of the flux barrier may be used as the region of the basic shape of the flux barrier. Furthermore, for example, if the entire flux barrier is located outside the design region as a result of applying a mapping to the region of the basic shape of the flux barrier, the flux barrier is erased. When using the technique improved from the technique described in Patent Document 1 as described above, the determination unit 414 performs at least one of adding, changing, and deleting a flux barrier to the original core.

[0083] Furthermore, for example, the determination unit 414 may determine the area of ​​the magnetic flux obstruction part by using a method improved from the method described in Non-Patent Document 1. In the method described in Non-Patent Document 1, the output y(x e If x is greater than or equal to 0, the state of the mesh is set to on. e is the center of gravity of the mesh. On the other hand, the output of NGnet in a certain mesh, y(x e ) is less than 0, the state of the mesh is set to off. In Non-Patent Document 1, a mesh is called a cell.

[0084] For example, in the method described in Non-Patent Document 1, the determination unit 414 determines the output y(x e For example, the determination unit 414 may change the threshold for the output y(x e ) is the threshold for the output y(x e ) may be smaller than the threshold for the output y(x e ) may be added to a positive real number. The determination unit 414 may also determine the output y(x e ) by a negative real number. The determination unit 414 may perform both addition of positive real numbers and addition of negative real numbers. The determination unit 414 may multiply the weighting coefficient for the normalized Gaussian function by a positive real number or a negative real number. For example, if the value of the normalized Gaussian function for a mesh that is not sampled is a positive value, the determination unit 414 may multiply the weighting coefficient by a negative real number. If the value of the normalized Gaussian function for a mesh that is not sampled is a negative value, the determination unit 414 may multiply the weighting coefficient by a positive real number. If the value of the normalized Gaussian function for a mesh that is not sampled is a positive value, the determination unit 414 may multiply the weighting coefficient by a positive real number. If the value of the normalized Gaussian function for a mesh that is sampled is a positive value, the determination unit 414 may multiply the weighting coefficient by a positive real number. If the value of the normalized Gaussian function for a mesh that is sampled is a negative value, the determination unit 414 may multiply the weighting coefficient by a negative real number. Note that, as described in the Background Art section, in the method described in Non-Patent Document 1, the weighting coefficient for the normalized Gaussian function is a design variable. Therefore, when the weighting coefficient for the normalized Gaussian function is multiplied by a positive real number or a negative real number, the design variable is changed. The determination unit 414 may perform all of the following, or may perform one or two of them: changing the threshold, adding a positive real number, and multiplying by a positive real number or a negative real number.

[0085] Even with the above, as with the improvement of the technique described in Patent Document 1, according to the distribution of generation probability, the greater the influence a position has on the characteristics of the core and the device, the more likely it is to be calculated as the position of a flux barrier (i.e., the more likely it is to be in the on state). Conversely, the smaller the influence a position has on the characteristics of the core and the device, the less likely it is to be calculated as the position of a flux barrier (i.e., the more likely it is to be in the off state). Therefore, it is possible to reduce the calculation load while increasing the probability that a sampled point is included in a magnetic flux obstruction portion.

[0086] As an improvement over the method described in Non-Patent Document 1, a method without sampling may be used. For example, the determination unit 414 determines the output y(x e ) may be changed. In this case, for example, the determination unit 414 may set a smaller threshold value for a mesh with a higher generation probability. Also, for example, the determination unit 414 may set a smaller threshold value for the NGnet output y(x e ) may be added to a positive real number or a negative real number. In this case, the determination unit 414 determines whether the output y(x e ) may be set to a larger positive real number. In addition, the lower the generation probability, the larger the NGnet output y(x e Alternatively, the determining unit 414 may increase the absolute value of the negative real number to be added to the normalized Gaussian function. Alternatively, the determining unit 414 may multiply the weighting coefficient for the normalized Gaussian function by a positive real number or a negative real number.

[0087] Note that calculating the characteristic values ​​of the equipment including the evaluation cores 721 and 731 by performing electromagnetic field analysis on the evaluation cores 721 and 731 as described above is preferable because it allows for easy and accurate calculation of the characteristic values ​​of the equipment. However, the characteristic values ​​of the equipment including the evaluation cores 721 and 731 do not have to be calculated by performing electromagnetic field analysis on the evaluation cores 721 and 731. For example, the determination unit 414 may calculate the characteristic values ​​of the equipment using a trained model (machine learning model) that has learned the relationship between an image including a magnetic flux obstruction portion and the characteristic values ​​of the equipment. The determination unit 414 may also calculate the characteristic values ​​of the equipment using an equivalent circuit method or the like. Note that the equivalent circuit method is a method of calculating the characteristic values ​​of the equipment using an equivalent circuit of the equipment. The equivalent circuit is expressed using, for example, resistance, inductance, and electromotive force. The equivalent circuit may also be expressed using capacitance.

[0088] In the following description, the information capable of identifying the region of the magnetic flux inhibition portion determined by the determination unit 414 in the above manner is also referred to as inhibition portion information MO. The output unit 415 outputs the inhibition portion information MO (step S506). In this embodiment, a case is exemplified in which the output unit 415 outputs the inhibition portion information MO to the output processing device 430. As described above, this embodiment also exemplified a case in which the output processing device 430 includes a computer display. In this case, the inhibition portion information MO output from the output unit 415 is displayed on the computer display.

[0089] The designer may design a core (a rotor core in this embodiment) based on the inhibition portion information MO. In this case, the designer determines information necessary for manufacturing the magnetic flux inhibition portions, such as the number, position, shape, and size of the magnetic flux inhibition portions, based on the magnetic flux inhibition portions (flux barriers in this embodiment) identified by the inhibition portion information MO. The information necessary for manufacturing the magnetic flux inhibition portions may include information regarding a manufacturing method for the magnetic flux inhibition portions.

[0090] The designer may design a core including a magnetic flux inhibiting portion in all or part of at least one of the magnetic flux inhibiting portion regions identified by the inhibition portion information MO. That is, the designer may design a core including a magnetic flux inhibiting portion in all or part of all of the magnetic flux inhibiting portion regions identified by the inhibition portion information MO, or may design a core including a magnetic flux inhibiting portion in all or part of some of the magnetic flux inhibiting portion regions identified by the inhibition portion information MO. For example, the designer may employ the magnetic flux inhibiting portion identified by the inhibition portion information MO itself. Alternatively, the designer may modify the magnetic flux inhibiting portion identified by the inhibition portion information MO. For example, if the shape of the magnetic flux inhibiting portion identified by the inhibition portion information MO is not smooth, the designer may modify the magnetic flux inhibiting portion to smooth the shape to facilitate manufacturing of the magnetic flux inhibiting portion. In this case, the ratio of the volume (or area) of the modified magnetic flux inhibiting portion to the volume (or area) of the magnetic flux inhibiting portion before modification is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. The number of magnetic flux inhibiting portions included in the core is preferably 0.5 to 1.5 times the number of magnetic flux inhibiting portions identified by the inhibiting portion information MO, more preferably 0.75 to 1.25 times, and even more preferably 1. The shortest distance between the representative point of the magnetic flux inhibiting portion before modification and the representative point of the magnetic flux inhibiting portion after modification is, for example, preferably 0.04 to 0.06 times the length of the core, more preferably 0.02 to 0.04 times, even more preferably 0.00 to 0.02 times, and most preferably 0 mm. Here, the length of the core refers to, for example, the maximum length of the core in a cross section perpendicular to the central axis of the core. In the example shown in FIG. 3 , the length of the core is the outer diameter of the rotor core 311 .

[0091] The device (IPMSM in this embodiment) designed as described above is manufactured using a manufacturing device. The manufacturing device itself may be a known manufacturing device. In the core manufacturing process, a core having a magnetic flux obstruction portion according to the above-described design is manufactured. If the magnetic flux obstruction portion is a flux barrier, for example, a cutting device that cuts a soft magnetic material plate is used to form the flux barrier in the core. The cutting may be performed by punching, laser processing, or other methods. The output unit 415 may output the obstruction portion information MO to a control device that controls the cutting device. In this case, the control device may control the cutting device based on the obstruction portion information MO. The output processing device 430 may be equipped with a control device.

[0092] <Hardware> As described above, the processing device 410 can be realized by using various types of hardware, and for example, can be realized by using the hardware shown in FIG.

[0093] 8, the processing device 410 includes a processor 801 , a main memory device 802 , an auxiliary memory device 803 , a communication circuit 804 , a signal processing circuit 805 , an image processing circuit 806 , an I / F circuit 807 , and a bus 808 .

[0094] The processor 801 performs overall control of the processing device 410. The processor 801 uses the main memory device 802 as a work area to execute programs stored in the auxiliary memory device 803. In this embodiment, the programs stored in the auxiliary memory device 803 include, for example, a program that executes the flowchart shown in FIG. 5. The processor 801 may be, for example, a CPU or a GPU. The main memory device 802 temporarily stores data. The auxiliary memory device 803 stores various types of data in addition to the programs executed by the processor 801.

[0095] The communication circuit 804 is a circuit for communicating with the outside of the processing device 410. The communication circuit 804 may perform wireless communication with the outside of the processing device 410 or may perform wired communication.

[0096] The signal processing circuit 805 performs various types of signal processing on signals received by the communication circuit 804 and signals input under the control of the processor 801. The image processing circuit 806 performs various types of image processing on signals input under the control of the processor 801. The signals that have undergone image processing by the image processing circuit 806 are output to the output processing device 430 equipped with a computer display via, for example, an I / F circuit 807.

[0097] The I / F circuit 807 exchanges data with devices communicatively connected to the I / F circuit 807. In FIG. 8 , the input processing device 420 and the output processing device 430 are shown as devices communicatively connected to the I / F circuit 807. However, the devices connected to the I / F circuit 807 are not limited to these. For example, a portable storage medium may be connected to the I / F circuit 807. Furthermore, when the output processing device 430 includes the control device described above, the communication circuit 804 and the output processing device 430 are communicatively connected to each other. In this case, the output processing device 430 (e.g., a user interface) communicatively connected to the I / F circuit 807 and the output processing device 430 (e.g., the control device described above) communicatively connected to the communication circuit 804 are separate devices.

[0098] The processor 801, main memory device 802, auxiliary memory device 803, signal processing circuit 805, image processing circuit 806, and I / F circuit 807 are connected to a bus 808. Communication between these components is performed via the bus 808. The hardware of the processing device 410 is not limited to the hardware shown in Fig. 8 as long as it can realize the functions of the processing device 410 described above. For example, the processing device 410 may include multiple processors 801.

[0099] (Calculation Example) Next, a calculation example will be described. In this calculation example, rotor core 311 of IPMSM 300 shown in FIG. 3 was used as an original core, and flux barriers were generated in the original core by the method of this embodiment and the method of Patent Document 1.

[0100] In this calculation example, the number of poles of the IPMSM 300 was set to 8. The number of slots of the IPMSM 300 was set to 24. The outer diameter of the stator core 321 was set to 55 mm. The outer diameter of the rotor core 311 was set to 27.5 mm. The residual magnetic flux density of the permanent magnets 312a to 312b was set to 1.2 T. The rotation speed of the IPMSM 300 was set to 1500 rpm (excitation frequency was set to 100 Hz). The advance angle was set to 40°. The effective value of the excitation current was set to 20 A. A real-valued genetic algorithm was used as the optimization calculation algorithm. The average torque value of the IPMSM was set to the objective function value.

[0101] As described in Patent Document 1, the torque was assumed to be Maxwell stress. Furthermore, the average torque was calculated based on the torque in each mesh. Furthermore, to ensure that the amount of calculations required for the method of this embodiment and the method described in Patent Document 1 were equivalent, the number of iterations in the optimization calculation (convergence calculation) was the same for each method. In other words, the solution obtained when the optimization calculation (convergence calculation) was performed the specified number of iterations was regarded as the optimal solution.

[0102] The average torque of the IPMSM with the flux barrier calculated by each method was determined as the average torque of the IPMSM when the optimal solution was obtained by the method of this embodiment and the method described in Patent Document 1. In addition, the average torque of the IPMSM 300 shown in Figure 3 was calculated.

[0103] The average torque of the IPMSM equipped with a flux barrier generated by the method of this embodiment was 82.4% higher than the average torque of the IPMSM 300 shown in FIG. 3 . On the other hand, the average torque of the IPMSM equipped with a flux barrier generated by the method described in Patent Document 1 was 55.7% higher than the average torque of the IPMSM 300 shown in FIG. 3 . This shows that, assuming the same amount of calculation, the method of this embodiment was able to calculate a superior optimal solution (flux barrier) than the method described in Patent Document 1. In other words, the method of this embodiment was able to converge to the optimal solution in a shorter time than the method described in Patent Document 1. It is believed that the method of this embodiment reduced the calculation load because the solution search range was narrower than the method described in Patent Document 1.

[0104] 9A and 9B are diagrams showing an example of a flux barrier generated by the method of this embodiment and the method described in Patent Document 1, respectively.

[0105] As shown in FIG. 9A , the method of this embodiment samples representative points of flux barriers based on the distribution of generation probability. Therefore, it is believed that flux barriers are generated concentratedly at positions that contribute significantly to the average torque of the IPMSM. On the other hand, as shown in FIG. 9B , the method described in Patent Document 1 does not consider the ease (or difficulty) of selecting each position in the design domain when generating flux barriers. Therefore, it is believed that the method described in Patent Document 1 also generated flux barriers at positions that contribute significantly to the average torque of the IPMSM. Furthermore, it is believed that the method described in Patent Document 1 generated numerous flux barriers over a wide area. Note that, as shown in FIGS. 9A and 9B , the method of this embodiment generated fewer flux barriers and each flux barrier was larger than the method described in Patent Document 1. Therefore, it is believed that the method of this embodiment can generate flux barriers that are easier to manufacture than the method described in Patent Document 1.

[0106] (Summary) In this embodiment, the processing device 410 calculates the distribution of a generation index that evaluates the ease of generating a magnetic flux inhibiting portion in the design region of the original core 711 based on the distribution of magnetic properties in the design region. The processing device 410 then determines the region of the magnetic flux inhibiting portion in the design region of the original core 711 based on the distribution of the generation index. Therefore, for example, the ease (and difficulty) of generating a magnetic flux inhibiting portion depending on the position of the design region of the original core 711 can be determined based on the magnetic properties before the magnetic flux inhibiting portion is generated. Therefore, for example, during the solution search process, it is possible to reduce the possibility of generating a magnetic flux inhibiting portion that does not contribute to improving the core characteristics. Therefore, for example, it is possible to generate a magnetic flux inhibiting portion that improves the core characteristics without imposing a large computational load.

[0107] Furthermore, in this embodiment, the processing device 410 selects a selection area from the design area of ​​the original core 711 based on the distribution of the generation index, and generates evaluation cores 721, 731 that include a magnetic flux obstruction portion in the selected area. The processing device 410 then calculates characteristic values ​​of a device that includes the evaluation cores 721, 731, and determines the area of ​​the magnetic flux obstruction portion in the design area based on the characteristic values. Therefore, for example, it is possible to generate a magnetic flux obstruction portion that improves the characteristics of the device based on the characteristic values ​​of the device, which are quantitative indexes.

[0108] In this embodiment, the processing device 410 samples points within the design area based on the distribution of the generation probability, and generates magnetic flux obstructions based on the sampled points. Therefore, for example, it is possible to quantitatively determine which positions within the core will be magnetic flux obstructions based on the generation probability. Therefore, for example, it is possible to more reliably generate magnetic flux obstructions that improve the core characteristics.

[0109] Furthermore, in this embodiment, the processing device 410 samples points within the design area as representative points of the magnetic flux obstruction portion based on the distribution of the generation probability. Therefore, for example, the attributes of the magnetic flux obstruction portion other than the representative point can be calculated without using the distribution of the generation probability. This allows, for example, an increased degree of freedom in generating the magnetic flux obstruction portion. Note that the processing device 410 may also calculate the attributes of the magnetic flux obstruction portion other than the representative point using the distribution of the generation probability.

[0110] In this embodiment, the processing device 410 generates a magnetic flux inhibiting portion based on the results of electromagnetic field analysis of the evaluation cores 721 and 731. Therefore, for example, it is possible to quantitatively evaluate the degree to which a magnetic flux inhibiting portion including a sampled point contributes to improving the core characteristics. Therefore, for example, it is possible to more reliably generate a magnetic flux inhibiting portion that improves the core characteristics.

[0111] In this embodiment, the processing device 410 generates a magnetic flux inhibiting portion by adding, modifying, or deleting a magnetic flux inhibiting portion to the original core 711. Note that modifying a magnetic flux inhibiting portion refers to, for example, changing at least one of the position, size, and shape of an existing magnetic flux inhibiting portion. Therefore, for example, a magnetic flux inhibiting portion can be generated by modifying the original core 711. Therefore, for example, components other than the magnetic flux inhibiting portion can be predetermined by the original core 711. This can reduce the computational load compared to, for example, generating the magnetic flux inhibiting portion and the components other than the magnetic flux inhibiting portion simultaneously.

[0112] Furthermore, in this embodiment, the processing device 410 calculates the distribution of magnetic properties based on the results of electromagnetic field analysis of the original core 711. Therefore, for example, even if there is no distribution of magnetic properties in the original core 711, it is possible to obtain the distribution of magnetic properties in the original core 711. Therefore, for example, original cores with various configurations can be used as the original core.

[0113] In this embodiment, the processing device 410 acquires area condition information that can identify an allowed area. The processing device 410 then generates a magnetic flux obstruction portion within the allowed area. Therefore, for example, by limiting the area in which the magnetic flux obstruction portion is generated to within the allowed area, the calculation load can be further reduced. Also, for example, it is possible to prevent a magnetic flux obstruction portion from being generated in a position within the design area where a magnetic flux obstruction portion should not exist.

[0114] In this embodiment, the processing device 410 uses, for example, the probability of magnetic flux obstruction as a generation index for evaluating the likelihood of magnetic flux obstruction, thereby making it possible to quantitatively evaluate, for example, the likelihood (and difficulty) of magnetic flux obstruction.

[0115] In this embodiment, the processing device 410 uses the distribution of representative values ​​of the magnetic properties in one period as the distribution of the magnetic properties. Therefore, for example, a distribution that more accurately reflects the magnetic properties of the core can be used as the distribution of the magnetic properties. Therefore, for example, it is possible to more reliably generate a magnetic flux inhibition portion that improves the characteristics of the core.

[0116] (Other Embodiments) The above-described embodiments of the present disclosure can be realized by a computer executing a program. Furthermore, a computer-readable recording medium on which the program is recorded and a computer program product such as the program can also be applied as embodiments of the present disclosure. Examples of recording media that can be used include flexible disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, magnetic tapes, non-volatile memory cards, and ROMs. Furthermore, the above-described embodiments of the present disclosure merely illustrate specific examples of how the present disclosure can be implemented, and the technical scope of the present disclosure should not be interpreted as being limited by these examples. In other words, the present disclosure can be implemented in various forms without departing from its technical concept or main features.

[0117] The present disclosure can be used, for example, to design and manufacture cores.

Claims

1. A processing device that performs processing to design a core having a magnetic flux inhibiting portion, comprising: an index calculation unit that calculates a distribution of generation indices that evaluate the ease of generating the magnetic flux inhibiting portion in a design area of an original core that serves as the prototype of the designed core, based on the distribution of magnetic properties in the design area; and a determination unit that determines the area of the magnetic flux inhibiting portion in the design area based on the distribution of the generation indices, wherein the design area is an area on a cut surface of the original core, and the cut surface of the original core is a cut surface in a direction perpendicular to the direction in which the magnetic flux inhibiting portion is viewed in a plane.

2. The processing device described in claim 1, wherein the determination unit selects a selection area from the design area based on the distribution of the generation index, generates an evaluation core having the magnetic flux obstruction section in the selection area, calculates characteristic values of a device having the evaluation core, and determines the area of the magnetic flux obstruction section in the design area based on the calculated characteristic values.

3. The processing device according to claim 2, wherein the determination unit samples points within the design area based on the distribution of the generation index, and selects the selected area based on the sampled points.

4. The processing device according to claim 3, wherein the determination unit samples a point within the design area as a representative point of the magnetic flux obstruction portion.

5. The processing device according to any one of claims 2 to 4, wherein the determination unit calculates the characteristic value of the device by performing an electromagnetic field analysis on the evaluation core.

6. A processing device according to any one of claims 2 to 5, wherein the determination unit generates the evaluation core by performing at least one of adding, changing, and deleting the magnetic flux obstruction unit from the design area.

7. The processing device according to any one of claims 1 to 6, further comprising a distribution calculation unit that calculates the distribution of magnetic properties in the design area based on the results of electromagnetic field analysis of the original core.

8. A processing device according to any one of claims 1 to 7, further comprising an acquisition unit that acquires premise information indicating prerequisites for generating the magnetic flux obstruction portion, the premise information including area condition information that can identify an allowed area that is allowed to be determined as the area of the magnetic flux obstruction portion in the core, and the determination unit determines the area of the magnetic flux obstruction portion in the core within the allowed area.

9. The processing device according to any one of claims 1 to 8, wherein the generation index is a generation probability of the magnetic flux obstruction portion.

10. The processing device according to any one of claims 1 to 9, wherein the distribution of the magnetic properties is a distribution of representative values of the magnetic properties in one period.

11. The processing device according to any one of claims 1 to 10, wherein the magnetic flux obstruction portion includes a gap portion.

12. The processing device according to any one of claims 1 to 11, wherein the magnetic property is magnetic flux density, magnetic field strength, or magnetic permeability.

13. A processing method for performing processing to design a core having a magnetic flux inhibiting portion, comprising: an index calculation step of calculating a distribution of generation indices that evaluate the ease of generating the magnetic flux inhibiting portion in a design area of an original core that serves as the prototype of the core after design, based on the distribution of magnetic properties in the design area; and a determination step of determining the area of the magnetic flux inhibiting portion in the design area based on the distribution of the generation indices, wherein the design area is an area on a cut surface of the original core, and the cut surface of the original core is a cut surface in a direction perpendicular to the direction in which the magnetic flux inhibiting portion is viewed in a plane.

14. A program for causing a computer to function as each part of the processing device according to any one of claims 1 to 12.

15. A core comprising the magnetic flux obstruction portion in all or part of at least one of the regions determined by the determination portion provided in the processing device according to any one of claims 1 to 12.

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