Degaussing risk index display method, degaussing risk index display device, and degaussing risk index display program

Abstract

To provide a demagnetization risk index display method that can easily grasp both risk of demagnetization to irreversible demagnetization of a permanent magnet and a level of the irreversible demagnetization.SOLUTION: A degaussing risk display method for displaying demagnetization risk of a permanent magnet of the present invention comprises steps of: generating a mesh division model of the permanent magnet; setting a permanent magnet B-H curve and a demagnetization starting point; performing a magnetic field analysis of an apparatus to be analyzed that includes a permanent magnet, and calculating a magnetic field and magnetic flux density at an operation point in each element of the mesh division model of the permanent magnet; determining whether each element is in a reversible demagnetization state or an irreversible demagnetization state from the magnetic field and magnetic flux density at the operating point; obtaining demagnetization risk index of each element by using a demagnetization risk as an index when it is in a reversible demagnetization state and by using a demagnetization risk as an index when it is in an irreversible demagnetization state; and contouring the demagnetization risk index of each element.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for displaying a demagnetization risk index of a permanent magnet, a demagnetization risk index display device, and a demagnetization risk index display program.

Background Art

[0002] Permanent magnets are used in many electrical devices, and it is important to grasp their magnetic properties in advance in the design of electrical devices. One of the magnetic properties of this permanent magnet is reversible demagnetization and irreversible demagnetization due to an external magnetic field. In reversible demagnetization, the residual magnetic flux density of the permanent magnet remains unchanged, but in irreversible demagnetization, even when the external magnetic field is removed, the residual magnetic flux density of the permanent magnet does not return to its original value but decreases. When irreversible demagnetization occurs, the magnetic force of the permanent magnet decreases, and the desired performance of the electrical device cannot be obtained. In addition, irreversible demagnetization of a permanent magnet also occurs due to temperature changes.

[0003] For this reason, for example, Patent Document 1 discloses a magnetic field analysis technique for a permanent magnet that analyzes the demagnetization margin until the operating point enters irreversible demagnetization with high accuracy.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, although the operating point in most regions of a permanent magnet is in the reversible demagnetization state, irreversible demagnetization may occur at the corner portions of the permanent magnet. In particular, when the thickness of the permanent magnet is reduced, it is likely to shift to irreversible demagnetization in the vicinity of the corners of the permanent magnet. If this portion of irreversible demagnetization is small, it has little effect on the performance of the electrical equipment. However, in order to optimize the shape and improve the quality of the permanent magnet, it may be necessary to grasp the degree of demagnetization of the portion that has entered irreversible demagnetization.

[0006] In the above prior art, since only the demagnetization margin at which the permanent magnet reaches irreversible demagnetization is analyzed, it is necessary to separately analyze the degree of demagnetization of the portion that has entered irreversible demagnetization. An object of the present invention is to solve the above problems and enable easy grasping of the demagnetization states of both the margin to irreversible demagnetization and the level of irreversible demagnetization of the permanent magnet.

Means for Solving the Problems

[0007] To solve the above problems, a Demagnetization risk display device's demagnetization magnetic risk index display method for indicating the demagnetization risk of the permanent magnet of the present invention includes The processing unit of the demagnetization risk display device steps of generating a mesh division model of the permanent magnet, setting a B-H curve and a demagnetization start point of the permanent magnet, performing a magnetic field analysis of an analysis target device including the permanent magnet, and calculating a magnetic field and a magnetic flux density of an operating point in each element of the mesh division model of the permanent magnet; determining whether each element is in a reversible state or an irreversible state from the magnetic field and the magnetic flux density of the operating point; obtaining a demagnetization risk index of each element using a demagnetization risk as an index when in a reversible state and a demagnetization rate as an index when in an irreversible state; and contour-displaying the demagnetization risk index of each element. It can be seen that in the step of obtaining the demagnetization risk index, when the element is in a reversible state, n times (n is a positive integer) of the max(0, H / Hb) value is obtained as the demagnetization risk index using the magnetic field H at the operating point and the magnetic field Hb at the demagnetization start point. When the element is in an irreversible state, the sum of the positive integer n and the demagnetization rate is obtained as the demagnetization risk index.

[0008] Also, a Demagnetization magnetic risk index The indicating device includes a model generation unit that generates a mesh segmentation model of the permanent magnet, a data setting unit that sets the B-H curve and the demagnetization start point of the permanent magnet, a magnetic field analysis unit that performs magnetic field analysis on the device under analysis including the permanent magnet and calculates the magnetic field and magnetic flux density at the operating point of each element of the mesh segmentation model of the permanent magnet, a state determination unit that determines whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point, a demagnetization risk index calculation unit that obtains a demagnetization risk index for each element using the demagnetization risk as an index for the elements included in the reversible state determined by the state determination unit and the demagnetization rate as an index for the elements included in the irreversible state determined by the state determination unit, and Perform control a display unit that , The demagnetization risk index calculation unit obtains n times (n is a positive integer) of the max(0, H / Hb) value as the demagnetization risk index using the magnetic field H at the operating point and the magnetic field Hb at the demagnetization start point for elements in a reversible state, and obtains the sum of the positive integer n and the demagnetization rate as the demagnetization risk index for elements in an irreversible state displays the demagnetization risk index of each element of the mesh segmentation model of the permanent magnet in a contour manner.

Advantages of the Invention

[0009] According to the present invention, since the demagnetization risk in the reversible state portion of the permanent magnet and the demagnetization rate in the irreversible state portion of the permanent magnet are simultaneously displayed in a contour manner, it is possible to simultaneously grasp the demagnetization risk and the demagnetized state of the permanent magnet by magnetic field analysis.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the attached drawings, elements having the same function may sometimes be denoted by the same reference numeral. Further, although the attached drawings show embodiments and characteristic examples in accordance with the principles of the present disclosure, these are for the purpose of understanding the present disclosure and are by no means used for interpreting the present disclosure in a limiting manner.

[0012] The description in this specification is merely a typical example and does not limit the scope of the claims of the present disclosure or its application examples in any sense. In this embodiment, the description is made in sufficient detail for those skilled in the art to implement the present disclosure. However, other implementations and forms are also possible, and it is necessary to understand that changes in configuration and structure and replacement of various elements can be made without departing from the scope and spirit of the technical idea of the present disclosure. Therefore, the following description should not be construed as being limited thereto.

[0013] First, with reference to FIG. 1, the operation of the demagnetized state in the magnetic field analysis of a permanent magnet will be described. In this specification, the state of reversible demagnetization of a permanent magnet is denoted as a reversible state, and the state of irreversible demagnetization is denoted as an irreversible state.

[0014] FIG. 1 is a diagram showing an example of a B-H curve of a permanent magnet, where the horizontal axis represents the magnetic field H and the vertical axis represents the magnetic flux density B. In FIG. 1, when a magnetic field in the direction opposite to the magnetization direction of the permanent magnet (the magnetic field in the negative direction of the horizontal axis in FIG. 1) is applied, the magnetic flux density of the permanent magnet decreases.

[0015] The relationship between the magnetic field and the magnetic flux density of the permanent magnet before demagnetization is shown by the B-H curve 1 in FIG. 1, and the magnetic flux density B when the magnetic field H is 0 is called the residual magnetic flux density 30 (value Br). The rising straight line part (H>Hb) on the right shoulder of the B-H curve 1 is the reversible region 40, and as long as the operating point 10 moves on this reversible region 40, the value Br of the residual magnetic flux density 30 remains unchanged.

[0016] In a rotating electrical machine such as a permanent magnet synchronous motor (PM motor), a magnetic field H is strongly applied in a direction opposite to the magnetization direction of the permanent magnet, causing H < Hb, and the operating point 10 may temporarily protrude from the reversible region 40 beyond the demagnetization start point 20 (also called the knee point). In this case, even if the magnetic field H weakens, the operating point 10 cannot return to the reversible region 40 and moves to an irreversible region 41 with the first branch point (demagnetization start point) 21 as the left end point (strictly speaking, it is a curve, but it can often be regarded as a straight line in engineering), and the operating point 10 shifts to the operating point 11 and moves left and right along the line of the irreversible region 41.

[0017] The value Br’ of the residual magnetic flux density 31 at magnetic field H = 0 in the irreversible region 41 is lower than the original Br. This phenomenon is called irreversible demagnetization. As long as it moves left and right on this irreversible region 41, the residual magnetic flux density 31 remains unchanged, but when H < Hb’ beyond the magnetic field Hb’ at the first branch point 21 at the left end of the irreversible region 41, the operating point 11 shifts to the operating point 12 on a new irreversible region 42 with the second branch point (demagnetization start point) 22 as the left end point. The value Br” of the residual magnetic flux density 32 at magnetic field H = 0 in the irreversible region 42 is even lower than the previous Br’.

[0018] That is, when a magnetic field exceeding the demagnetization start points such as the demagnetization start point 20, the first branch point 21, and the second branch point 22 is applied to the permanent magnet, the permanent magnet demagnetizes and finally settles into a certain irreversible state.

[0019] In this specification, the value obtained by subtracting the ratio of the residual magnetic flux density of the permanently magnetized in the irreversible state to the residual magnetic flux density of the non-demagnetized permanently magnet in the reversible state (such as Br’ / Br, Br” / Br, etc.) from 1 (1 - ratio of residual magnetic flux density) is defined as the demagnetization rate, which indicates the demagnetized state of the permanently magnetized in the irreversible state.

[0020] Also, in this specification, when the operating point is on the B-H curve 1 of the residual magnetic flux density 30 (value Br) and undergoes reversible demagnetization, it is assumed that the permanent magnet is in a reversible state. And when the operating point is on the B-H curve 41 of the residual magnetic flux density 31 (value Br'), or on the B-H curve 42 of the residual magnetic flux density 32 (value Br''), etc., it is assumed that the permanent magnet is in an irreversible state. That is, from the magnetic field and magnetic flux density of the operating point and the B-H curve before demagnetization, when the operating point is on the line of the reversible region 40 of the B-H curve before demagnetization, the permanent magnet is determined to be in a reversible state, and when it is not linear, it is determined to be in an irreversible state.

[0021] In the present invention, as described above, in order to easily grasp the demagnetized state of the permanent magnet by magnetic field analysis, in the irreversible state, the demagnetization rate, which is the value obtained by subtracting the ratio of the residual magnetic flux density before and after demagnetization from 1, is used as an index to indicate the demagnetized state. In the reversible state, the ratio of the magnetic field of the operating point to the magnetic field of the demagnetization start point (H / Hb) is used as the demagnetization risk, and the demagnetization state is indicated using the demagnetization risk as an index.

[0022] By the way, the magnetic field H of the operating point can take not only negative values but also positive values. Since the magnetic field Hb of the demagnetization start point <0, H / Hb <0, but the demagnetization risk needs to be obtained as 0. Therefore, the demagnetization risk is obtained as the max(0, H / Hb) value. Here, max(0, H / Hb) means taking the larger value between 0 and H / Hb.

[0023] Then, the present invention introduces a demagnetization risk index indicating the demagnetized state of each element of the magnetic field analysis, determines whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density of the operating point of the element analyzed by the magnetic field analysis. When it is in a reversible state, n times the demagnetization risk (n is a positive integer) is obtained as the demagnetization risk index. When it is in an irreversible state, the sum of the positive integer n and the demagnetization rate is obtained as the demagnetization risk index, and the demagnetization risk index of each element is displayed in contour.

[0024] Since the demagnetization risk index indicates the demagnetization risk from 0 to n and the demagnetization rate from n to n + 1, the smaller the demagnetization risk index, the smaller the influence of demagnetization, and the larger the demagnetization risk index, the larger the influence of demagnetization. Therefore, the demagnetization risk index shows the influence of demagnetization uniformly in the reversible state and the irreversible state.

[0025] Note that the demagnetization risk is a value smaller than 1. If n = 1, the demagnetization risk index can indicate the demagnetized state. However, by setting n as a positive integer larger than 1, the resolution of the demagnetization risk in the contour display can be improved, making it easier to perform the evaluation.

[0026] In the above, in the reversible state, it was explained that the demagnetization risk is defined using the ratio of the magnetic field at the operating point to the magnetic field at the demagnetization start point (H / Hb) as an index. However, (Br - B) / (Br - Bb) may be used as the demagnetization risk using the residual magnetic flux density Br in the reversible region, the magnetic flux density B at the operating point, and the magnetic flux density Bb at the demagnetization start point. In this case, n times the value of max(0, (Br - B) / (Br - Bb)) (n is a positive integer) is obtained as the demagnetization risk index.

[0027] Next, the demagnetization risk index display method of the embodiment will be described in detail with reference to the flowchart of FIG. 2.

[0028] First, in step S21, based on the analysis by the finite element method or the like, the mesh division data of the overall model of the electrical equipment including the permanent magnet to be analyzed is set. At this time, if there is symmetry in the object to be analyzed, it is also possible to utilize the symmetry and cut out a part for analysis, so it may be only a part of the mesh division data to be prepared.

[0029] Then, in step S22, set the B-H curve data of the permanent magnet and other magnetic materials and the demagnetization start point of the permanent magnet. The input data of the B-H curve is usually a point sequence of magnetic field H and magnetic flux density B, but other forms such as continuous functions may be input. The demagnetization start point is set as the departure point from the straight line part in the second quadrant of the B-H curve of the permanent magnet, but it may also be set by the user or automatically set in the computer. In the case of automatic setting, for example, a reduction rate of the residual magnetic flux density of 0.999 or less is regarded as irreversible demagnetization.

[0030] In step S23, using the mesh division data input in step S21 and the B-H curve input in step S22, perform magnetic field analysis of the electrical equipment including the permanent magnet by the finite element method or the like. Thereby, the magnetic field and magnetic flux density of each element of the mesh-divided permanent magnet are calculated, and the operating point of each element in the B-H curve is obtained (calculate the magnetic field and magnetic flux density of each element by magnetic field analysis to obtain the operating point). Next, the following steps are performed for each element.

[0031] In step S24, determine whether the operating point obtained in step S23 exceeds the demagnetization start point of the B-H curve. If not (No in S24), proceed to step S26. If it exceeds (Yes in S24), proceed to step S25, update the B-H curve used for magnetic field analysis according to the position of the operating point in step S25, and then proceed to step S26.

[0032] In step S26, determine whether the final time step has been reached. If it has (Yes in S26), proceed to step 28. If not (No in S26), proceed to step 27, advance the time step by one, and perform step S23.

[0033] In step S28, in this transient magnetic field analysis, if the operating point exceeds the demagnetization start point even once (Yes in S28), the process proceeds to step S29. In step S29, a value obtained by subtracting from 1 the ratio of the residual magnetic flux density of the element to the residual magnetic flux density of the element that has not been demagnetized (1 - residual magnetic flux density ratio) is calculated as the demagnetization rate, and a magnification n (n: positive integer) is added to obtain the demagnetization risk index, and the process proceeds to step S31. Also, in step S28, in this transient magnetic field analysis, if the operating point does not exceed the demagnetization start point (No in S28), the process proceeds to step S30. In step S30, the ratio of the magnetic field at the operating point to the magnetic field at the demagnetization start point (H / Hb) is calculated as the demagnetization risk, multiplied by n to obtain the demagnetization risk index, and the process proceeds to step S31.

[0034] In step S31, the demagnetization risk index of each element obtained by mesh-dividing the permanent magnet, which was obtained in step S29 or step S30, is displayed in a contour.

[0035] In the above, an example of displaying the demagnetization risk index of the permanent magnet in a contour after the magnetic field analysis has been completed was described. However, during the intermediate stage of the transient analysis, the demagnetization risk index of the permanent magnet may be displayed in a contour at any time. In this case, step S26 is brought after step S31, and in step S31, a process of displaying the demagnetization risk index of each element at each time step in a contour is performed.

[0036] FIG. 3A is a diagram showing an example of the contour display of the demagnetization risk index of each element obtained by mesh-dividing the permanent magnet in step S211 described in FIG. 2. In FIG. 3A, the contour display of the demagnetization risk index when the display magnification n of the demagnetization risk is set to 1 (n = 1) is shown. The permanent magnet is shown as a thick-line rectangular region (a horizontally long rectangular region), and the values of the demagnetization risk index of each element of the mesh-divided permanent magnet are assigned to color codes (color palettes) with different display colors and displayed. Since it is displayed in different display colors according to the demagnetization risk index, it is possible to identify whether each element is in a reversible state or an irreversible state from the display color of each element, grasp the distribution of the reversible / irreversible states of the permanent magnet, and simultaneously grasp the demagnetization risk and demagnetized state of the permanent magnet.

[0037] The demagnetization risk index, which uses the demagnetization rate with a value in the range of 0 to 1.0 and the demagnetization risk with a value in the range of 0 to 1.0 as indicators, will have a value in the range of 0 to 2.0 when n = 1. In FIG. 3A, the demagnetization risk index is displayed in the range of values from 0 to 1.5, that is, the demagnetization risk is in the range of values from 0 to 1.0, and the demagnetization rate is in the range of values from 0 to 0.5. Thus, by narrowing the range of the demagnetization risk index to which the color code is assigned, the resolution of the demagnetization risk index when displayed as a contour can be increased, so that the demagnetized state of the permanent magnet can be grasped in detail.

[0038] Next, a display example of a contour display that can easily distinguish between the reversible state and the irreversible state will be described.

[0039] FIG. 3B shows a contour display in which when the demagnetization risk index of each element obtained by mesh-dividing the permanent magnet is displayed as a contour, the boundary between the reversible state elements and the irreversible state elements is shown as a thick line for distinguishable display. Since the demagnetization risk index (demagnetization risk) of the reversible state elements and the demagnetization risk index (1 + demagnetization rate) of the reversible state elements are assigned different color codes, they can be distinguished, but by showing the boundary as a thick line, the discrimination becomes easier.

[0040] Also, when the demagnetization risk index of each element obtained by mesh-dividing the permanent magnet is displayed as a contour, different filling patterns or textures may be used for the reversible state elements and the irreversible state elements to perform a contour display of the color code assigned to the demagnetization risk index. This can also make it easy to distinguish between the reversible state and the irreversible state.

[0041] In FIG. 3B, although not shown, the volume ratio of the reversible state element and the irreversible state element, or the ratio of the volume of the irreversible state element to the total volume of the permanent magnet may be displayed. This makes it possible to easily grasp the demagnetized state of the permanent magnet.

[0042] Next, the configuration of the demagnetization risk index display device 101 of the embodiment will be described. FIG. 4 is a system configuration diagram of the demagnetization risk index display device 101 of the embodiment.

[0043] The demagnetization risk index display system 100 includes a demagnetization risk index display device 101 that obtains the demagnetization risk index of each element obtained by mesh-dividing a permanent magnet, a display device 102 that performs a contour display of the demagnetization risk index such as a display, a storage device 103 that stores calculation data as a file, and an input device 104 that performs an analysis operation instruction and data input such as a mouse and a keyboard.

[0044] Specifically, the demagnetization risk index display device 101 is a computer and has a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM, an HDD (Hard Disk Drive), an input / output I / F (Interface), a communication I / F, and a media I / F, which are not shown.

[0045] The CPU operates based on a program stored in the ROM or the HDD and executes the demagnetization risk index display process described with reference to FIG. 2. The ROM stores a boot program executed when the computer is started, a program related to the hardware of the computer, and the like.

[0046] The CPU controls the input device 104 and the display device 102 via the input / output I / F. The CPU acquires data from the input device 104 via the input / output I / F and outputs the generated data to the display device 102.

[0047] The HDD stores programs executed by the CPU and data used by the programs. The communication I / F receives data from other devices via a communication network or network and outputs it to the CPU, and also transmits data generated by the CPU to other devices via the communication network or network.

[0048] The media I / F reads a program or data stored in a recording medium and outputs it to the CPU via the RAM. The recording medium is an optical recording medium such as a DVD (Digital Versatile Disc) or PD (Phase change rewritable Disk), a magneto-optical recording medium such as an MO (Magneto Optical disk), a magnetic recording medium, a conductor memory tape medium, or a semiconductor memory, etc.

[0049] The CPU loads a program related to the target process from the recording medium onto the RAM via the media I / F and executes the loaded program. Also, the CPU may read a program related to the target process from other devices via the communication network or network by the communication I / F.

[0050] The input device 104 is, for example, a keyboard or a mouse, and is used for inputting input data necessary for analysis including the B-H curve to the demagnetization risk index display device 101, specifying the reading and writing of data files storing the input data, executing calculations, etc.

[0051] The storage device 103 stores, as files, input data necessary for analysis including the B-H curve input by the input device 104 and calculation data such as the demagnetization risk index calculated by the demagnetization risk index display device 101.

[0052] Note that in FIG. 4, the storage device 103 is arranged outside the demagnetization risk index display device 101, but it may also be installed inside the demagnetization risk index display device 101. Also, the demagnetization risk index display device 101 may be connected to the display device 102, the storage device 103, and the input device 104 via a network.

[0053] Next, the configuration of the demagnetization risk index display device 101 will be described with reference to the functional block diagram of FIG. 5. Each functional block of the demagnetization risk index display device 101 in FIG. 5 realizes the function of each block when the CPU of the demagnetization risk index display device 101 executes a program.

[0054] The model generation unit 51 is a processing unit that generates a mesh division model of the permanent magnet. Specifically, on the premise of analysis by the finite element method or the like, mesh division data of the overall model of the electrical device including the permanent magnet to be analyzed is set. At this time, since it is also possible to cut out a part for analysis by utilizing the symmetry of the object to be analyzed, it is sufficient to prepare only a part of the mesh division data.

[0055] The data setting unit 52 sets the B-H curve and the demagnetization start point of the permanent magnet. Specifically, the B-H curve data of the permanent magnet and other magnetic materials and the demagnetization start point of the permanent magnet are set. The input data of the B-H curve is usually a point sequence of the magnetic field H and the magnetic flux density B, but it may be input in other forms such as a continuous function. The demagnetization start point is set as the departure point from the straight line part in the second quadrant of the B-H curve of the permanent magnet.

[0056] The magnetic field analysis unit 53 performs a magnetic field analysis of the device to be analyzed including the permanent magnet, and calculates the magnetic field and magnetic flux density at the operating point of each element of the mesh division model of the permanent magnet. Specifically, using the mesh division data generated by the model generation unit 51 and the B-H curve set by the data setting unit 52, a magnetic field analysis of the electrical device including the permanent magnet is performed by the finite element method or the like. Thereby, the magnetic field and magnetic flux density of each element of the mesh-divided permanent magnet are calculated, and the operating point on the B-H curve is obtained.

[0057] The state determination unit 54 determines whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point. Specifically, from the magnetic field and magnetic flux density at the operating point and the B-H curve before demagnetization, if the operating point is on the line of the reversible region 40 of the B-H curve before demagnetization, it is determined to be in a reversible state, and if it is not linear, it is determined to be in an irreversible state.

[0058] Further, the state determination unit 54 determines whether or not the operating point obtained by the magnetic field analysis unit 53 exceeds the demagnetization start point of the B-H curve. Then, when the operating point exceeds the demagnetization start point of the B-H curve, the state determination unit 54 updates the B-H curve used by the magnetic field analysis unit 53 for magnetic field analysis (for example, the irreversible region 41 shown in FIG. 1).

[0059] The demagnetization risk index calculation unit 55 obtains the demagnetization risk index of each element by using the demagnetization risk as an index for the elements included in the reversible state determined by the state determination unit 54 and using the demagnetization rate as an index for the elements included in the irreversible state determined by the state determination unit 54.

[0060] Specifically, the demagnetization risk index calculation unit 55 subtracts the ratio (Br’ / Br, Br” / Br, etc.) of the residual magnetic flux density of the permanent magnet that has become in the irreversible state to the residual magnetic flux density of the non-demagnetized permanent magnet in the reversible state from 1 (1 - ratio of residual magnetic flux density), and uses this value as the demagnetization rate. Then, for the elements in the reversible state, the demagnetization risk index calculation unit 55 uses the magnetic field H at the operating point and the magnetic field Hb at the demagnetization start point, and takes the max(0, H / Hb) value as the demagnetization risk, and takes n times (n is a positive integer) of the demagnetization risk as the demagnetization risk index. For the elements in the irreversible state, the demagnetization risk index calculation unit 55 obtains the sum of the positive integer n (display magnification) and the demagnetization rate as the demagnetization risk index.

[0061] Further, for the elements in the reversible state, the demagnetization risk index calculation unit 55 may use the residual magnetic flux density Br in the reversible state, the magnetic flux density B at the operating point, and the magnetic flux density Bb at the demagnetization start point, and take n times (n is a positive integer) of the max(0, (Br - B) / (Br - Bb)) value as the demagnetization risk index. For the elements in the irreversible state, the demagnetization risk index calculation unit 55 obtains the sum of the positive integer n and the demagnetization rate as the demagnetization risk index.

[0062] The display unit 56 controls the display device 102 to perform a contour display of the demagnetization risk index of each element of the mesh division model of the permanent magnet. Specifically, the display unit 56 assigns the value of the demagnetization risk index of each element of the mesh-divided permanent magnet to the display color code (color palette) and displays it on the display device 102 in FIG. 4.

[0063] The display unit 56 contour - displays in a distinguishable manner by thick - lining the boundary between the reversible - state elements and the irreversible - state elements, or the display unit 56 performs a contour - display of the color - code assigned to the demagnetization risk index with different filling patterns or textures for the reversible - state elements and the irreversible - state elements. Furthermore, the display unit 56 may be configured to display a value indicating the volume ratio of the reversible - state elements to the irreversible - state elements, or the ratio of the volume of the irreversible - state elements to the volume of the entire magnet.

[0064] According to the above - described embodiment, the demagnetization risk of the permanent magnet and the demagnetization rate in the case of demagnetization can be grasped simultaneously before the prototype production. Thus, the optimization of the arrangement of the permanent magnet, the optimization of the thickness and length of the permanent magnet can be achieved, contributing to the reduction of the number of prototype productions and the improvement of the cost - performance of the electrical equipment using the permanent magnet.

[0065] Also, the present invention is not limited to the above - described embodiments, and various modifications are included. The above - described embodiments have been described in detail for easy understanding of the present invention and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.

Explanation of Reference Numerals

[0066] 1 B - H curve 10, 11, 12 Operating points 20, 21, 22 Demagnetization start points 30, 31, 32 Residual magnetic flux densities 51 Model generation unit 52 Data setting unit 53 Magnetic field analysis unit 54 State determination unit 55 Demagnetization risk index calculation unit 56 Display unit

Claims

A method for displaying a demagnetization risk index of a demagnetization risk display device for displaying the demagnetization risk of a permanent magnet, comprising: The processing unit of the demagnetization risk display device:[[]] Generating a mesh segmentation model of the permanent magnet; Setting the B-H curve and the demagnetization start point of the permanent magnet; Performing a magnetic field analysis of the device under analysis including the permanent magnet, and calculating the magnetic field and magnetic flux density at the operating point of each element of the mesh segmentation model of the permanent magnet; Determining whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point; When it is in a reversible state, using the demagnetization risk as an index, and when it is in an irreversible state, using the demagnetization rate as an index, to obtain the demagnetization risk index of each element; Contour-displaying the demagnetization risk index of each element, and The step of obtaining the demagnetization risk index:[[]] When the element is in a reversible state, using the magnetic field H at the operating point and the magnetic field Hb at the demagnetization start point, obtaining n times (n is a positive integer) of the value of max(0, H / Hb) as the demagnetization risk index; When the element is in an irreversible state, obtaining the sum of a positive integer n and the demagnetization rate as the demagnetization risk index A demagnetization risk index display method characterized by the above. A method for displaying a demagnetization risk index of a demagnetization risk display device for displaying the demagnetization risk of a permanent magnet, comprising: The processing unit of the demagnetization risk display device:[[]] Generating a mesh segmentation model of the permanent magnet; Setting the B-H curve and the demagnetization start point of the permanent magnet; Performing a magnetic field analysis of the device under analysis including the permanent magnet, and calculating the magnetic field and magnetic flux density at the operating point of each element of the mesh segmentation model of the permanent magnet; Determining whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point; When it is in a reversible state, using the demagnetization risk as an index, and when it is in an irreversible state, using the demagnetization rate as an index, to obtain the demagnetization risk index of each element; Contour-displaying the demagnetization risk index of each element, and The step of obtaining the demagnetization risk index:[[]] When the element is in a reversible state, using the residual magnetic flux density Br in the reversible region, the magnetic flux density B at the operating point, and the magnetic flux density Bb at the demagnetization start point, obtaining n times (n is a positive integer) of the value of max(0, (Br - B) / (Br - Bb)) as the demagnetization risk index; When the element is in an irreversible state, the sum of a positive integer n and the demagnetization rate is obtained as the demagnetization risk index. A demagnetization risk index display method characterized by this.

3. In the demagnetization risk index display method according to Claim 1 or Claim 2, the processing unit of the demagnetization risk display device, in the step of contour-displaying the demagnetization risk index of each element, the boundary between the reversible state elements and the irreversible state elements is contour-displayed on the display unit so as to be distinguishable. A demagnetization risk index display method characterized by this.

4. In the demagnetization risk index display method according to Claim 3, the processing unit of the demagnetization risk display device, in the step of contour-displaying the demagnetization risk index of each element, further, the volume ratio of the reversible state elements to the irreversible state elements or the ratio of the volume of the irreversible state elements to the volume of the entire magnet is displayed on the display unit. A demagnetization risk index display method characterized by this.

5. A demagnetization risk index display device for displaying the demagnetization risk of a permanent magnet, a model generation unit for generating a mesh division model of the permanent magnet, a data setting unit for setting the B-H curve and the demagnetization start point of the permanent magnet, a magnetic field analysis unit that performs a magnetic field analysis of the device to be analyzed including the permanent magnet and calculates the magnetic field and magnetic flux density at the operating point in each element of the mesh division model of the permanent magnet, a state determination unit that determines whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point, a demagnetization risk index calculation unit that obtains the demagnetization risk index of each element using the demagnetization risk as an index for the elements included in the reversible state determined by the state determination unit and the demagnetization rate as an index for the elements included in the irreversible state determined by the state determination unit, a display unit that performs control to contour-display the demagnetization risk index of each element of the mesh division model of the permanent magnet, and is provided with, the demagnetization risk index calculation unit, for elements in a reversible state, using the magnetic field H at the operating point and the magnetic field Hb at the demagnetization start point, n times the value of max(0, H / Hb) (n is a positive integer) is obtained as the demagnetization risk index, for elements in an irreversible state, the sum of a positive integer n and the demagnetization rate is obtained as the demagnetization risk index. A demagnetization risk index display device characterized by this.

6. A demagnetization risk index display device for displaying the demagnetization risk of a permanent magnet a model generation unit for generating a mesh division model of the permanent magnet, a data setting unit for setting the B-H curve and the demagnetization start point of the permanent magnet, Performing magnetic field analysis of the device under analysis including the permanent magnet, and calculating the magnetic field and magnetic flux density at the operating point for each element of the mesh division model of the permanent magnet, a magnetic field analysis unit; A state determination unit that determines whether each of the elements is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point; A demagnetization risk index calculation unit that obtains a demagnetization risk index for each element, using the demagnetization risk as an index for the elements included in the reversible state determined by the state determination unit and the demagnetization rate as an index for the elements included in the irreversible state determined by the state determination unit; A display unit that performs control to contour-display the demagnetization risk index for each element of the mesh division model of the permanent magnet, and is provided with: The demagnetization risk index calculation unit is For elements in the reversible state, using the residual magnetic flux density Br in the reversible state, the magnetic flux density B at the operating point, and the magnetic flux density Bb at the demagnetization start point, obtaining n times (n is a positive integer) of the value of max(0, (Br - B) / (Br - Bb)) as the demagnetization risk index; For elements in the irreversible state, obtaining the sum of a positive integer n and the demagnetization rate as the demagnetization risk index A demagnetization risk index display device characterized by the above.

7. In the demagnetization risk index display device according to claim 5 or claim 6, The display unit contour-displays in a distinguishable manner the boundary between the elements in the reversible state and the elements in the irreversible state A demagnetization risk index display device characterized by the above.

8. In the demagnetization risk index display device according to claim 7, The display unit further displays the volume ratio of the elements in the reversible state and the elements in the irreversible state, or the ratio of the volume of the elements in the irreversible state to the volume of the entire magnet A demagnetization risk index display device characterized by the above.

9. A demagnetization risk index display program for displaying the demagnetization risk of a permanent magnet, which causes a computer to Generate a mesh division model of the permanent magnet; Set the B-H curve and demagnetization start point of the permanent magnet; Perform magnetic field analysis of the device under analysis including the permanent magnet, and calculate the magnetic field and magnetic flux density at the operating point for each element of the mesh division model of the permanent magnet; Determine whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density at the operating point; When the element is in the reversible state, using the demagnetization risk as an index, and when the element is in the irreversible state, using the demagnetization rate as an index, obtain the demagnetization risk index for each element; Contour-display the demagnetization risk index for each element, and has: ​ The step of obtaining the demagnetization risk index is as follows: When the element is in a reversible state, using the magnetic field H of the operating point and the magnetic field Hb of the demagnetization start point, n times (n is a positive integer) of the max(0, H / Hb) value is obtained as the demagnetization risk index. When the element is in an irreversible state, a demagnetization risk index display program for obtaining the sum of a positive integer n and the demagnetization rate as the demagnetization risk index.

10. A demagnetization risk index display program for displaying the demagnetization risk of a permanent magnet, on a computer, generating a mesh division model of the permanent magnet; setting the B-H curve and the demagnetization start point of the permanent magnet; performing a magnetic field analysis of the device to be analyzed including the permanent magnet, and calculating the magnetic field and magnetic flux density of the operating point of each element of the mesh division model of the permanent magnet; determining whether each element is in a reversible state or an irreversible state from the magnetic field and magnetic flux density of the operating point; when the element is in a reversible state, using the demagnetization risk as an index, and when the element is in an irreversible state, using the demagnetization rate as an index, obtaining the demagnetization risk index of each element; contour-displaying the demagnetization risk index of each element, and the step of obtaining the demagnetization risk index is as follows: when the element is in a reversible state, using the residual magnetic flux density Br in the reversible region, the magnetic flux density B of the operating point, and the magnetic flux density Bb of the demagnetization start point, n times (n is a positive integer) of the max(0, (Br - B) / (Br - Bb)) value is obtained as the demagnetization risk index; when the element is in an irreversible state, a demagnetization risk index display program for obtaining the sum of a positive integer n and the demagnetization rate as the demagnetization risk index.

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