Computer program, method for creating a lookup table, and information processing device.

Abstract

This invention provides a computer program that can reduce the burden of creating lookup tables for determining the flux linkage of electromagnetic devices having windings. [Solution] A computer program that causes a computer to perform a process to create a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the electromagnetic device, wherein the program transforms the component axes of multiple currents flowing through each winding so as to broaden the numerical range in which the change in flux linkage for the currents flowing through each winding is gradual and narrow the numerical range in which the change in flux linkage is steep, performs a magnetic field analysis based on the analysis model for the multiple currents whose component axes have been transformed, and causes the computer to perform a process to associate the flux linkage calculated by the magnetic field analysis with the currents.

Description

Technical Field

[0001] The present disclosure relates to a computer program, a method for creating a lookup table, and an information processing apparatus.

Background Art

[0002] In the development of an electric circuit including a transformer, a simulation apparatus for simulating its operation is used. In order to simulate the operation of the electric circuit in detail and accurately, a magnetic field analysis program for simulating the operation of the transformer and a circuit simulator for simulating the operations of the primary circuit and the secondary circuit constituting the electric circuit are interconnected. In the transformer operation simulator, for each simulation step corresponding to each time point in time series, a lookup table is called to simulate the operation of the transformer in detail, and the operation of the electric circuit is simulated using the simulation result.

[0003] The magnetic field analysis program creates and stores in advance a lookup table (LUT: Lookup table) representing characteristics such as the mutual magnetic flux according to the driving state by magnetic field analysis of an analysis model representing the shape and electromagnetic characteristics of the windings and core constituting the transformer. The transformer operation simulator refers to the LUT obtained by magnetic field analysis and simulates the operation of the transformer.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, it was necessary to perform magnetic field analysis by varying the current values ​​of the primary and secondary windings, and then create a LUT that correlates the flux linkage and current of each winding at each calculation point, which resulted in a heavy workload for creating the LUT. For example, in cases where the flux linkage changes significantly, such as in a transformer, the load on creating a LUT (Lookup Unit) increases. Specifically, when the range over which the flux linkage of the primary and secondary windings changes significantly with respect to the primary and secondary currents is wide, it becomes necessary to finely adjust the values ​​of the primary and secondary currents and perform magnetic field analysis, resulting in an enormous number of calculation points. Similar technical problems exist in electromagnetic devices other than transformers.

[0006] The purpose of this disclosure is to provide a computer program, a lookup table creation method, and an information processing device that can reduce the burden of creating a LUT for determining the flux linkage of an electromagnetic device having windings. [Means for solving the problem]

[0007] The computer program relating to this disclosure is a computer program that causes a computer to perform a process to create a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the electromagnetic device, and which converts the component axes of the multiple currents flowing through each winding so as to broaden the numerical range in which the change in magnetic flux linkage with respect to the currents flowing through each winding is gradual and narrow the numerical range in which the change in magnetic flux linkage is steep, performs a magnetic field analysis based on the analysis model with respect to the multiple currents whose component axes have been converted, and causes the computer to perform a process to associate the magnetic flux linkage calculated by the magnetic field analysis with the currents whose component axes have been converted.

[0008] The lookup table creation method according to this disclosure is a method for creating a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the electromagnetic device, wherein the computer transforms the component axes of the multiple currents flowing through each winding so as to broaden the numerical range in which the change in flux linkage with respect to the currents flowing through each winding is gradual and narrow the numerical range in which the change in flux linkage is steep, performs a magnetic field analysis based on the analysis model with respect to the multiple currents whose component axes have been transformed, and associates the flux linkage calculated by the magnetic field analysis with the currents whose component axes have been transformed.

[0009] The information processing apparatus according to this disclosure includes a processing unit that performs a process to create a lookup table for simulating the operation of an electromagnetic device having a plurality of windings based on an analysis model of the electromagnetic device, wherein the processing unit transforms the component axes of the plurality of currents flowing through each winding so as to broaden the numerical range in which the change in magnetic flux linkage with respect to the currents flowing through each winding is gradual and narrow the numerical range in which the change in magnetic flux linkage is steep, performs a magnetic field analysis based on the analysis model with respect to the plurality of currents whose component axes have been transformed, and performs a process to associate the magnetic flux linkage calculated by the magnetic field analysis with the currents whose component axes have been transformed. [Effects of the Invention]

[0010] According to this disclosure, the burden of creating a LUT for determining the flux linkage of an electromagnetic device having windings can be reduced. [Brief explanation of the drawing]

[0011] [Figure 1] This is a block diagram showing the configuration of the information processing device according to Embodiment 1 of this disclosure. [Figure 2] This is a schematic diagram showing a single-phase transformer. [Figure 3] This is a schematic diagram showing the configuration of an electrical circuit including a transformer. [Figure 4] This is a conceptual diagram illustrating the overview of coupled analysis performed by an information processing device. [Figure 5] It is a conceptual diagram showing the first and second LUTs that have not been normalized and axis-rotated. [Figure 6] It is a graph representing the mutual flux linkage of the primary winding. [Figure 7] It is a graph representing the mutual flux linkage of the secondary winding. [Figure 8] It is a conceptual diagram showing the resolution of the primary current and the error of the mutual flux linkage. [Figure 9] It is a conceptual diagram showing the steep region of the mutual flux linkage with respect to the current in the primary winding. [Figure 10] It is a graph representing the primary magnetic flux with respect to the normalized and axis-rotated current. [Figure 11] It is a graph representing the secondary magnetic flux with respect to the normalized and axis-rotated current. [Figure 12] It is a flowchart showing the processing procedure related to the creation of the first and second LUTs according to Embodiment 1. [Figure 13] It is a flowchart showing the processing procedure related to the transformer operation simulation. [Figure 14] It is a flowchart showing the processing procedure related to the creation of the first and second LUTs according to Embodiment 2. [Figure 15] It is a graph representing the normalized and axis-rotated first magnetic flux. [Figure 16] It is a graph representing the normalized and axis-rotated second magnetic flux. [Figure 17] It is a schematic diagram showing a three-phase transformer. [Figure 18] It is a graph representing the normalized and axis-rotated first to third magnetic fluxes with respect to the normalized and axis-rotated first current. [Figure 19] It is a graph representing the normalized and axis-rotated first to third magnetic fluxes with respect to the normalized and axis-rotated second current.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, the present disclosure will be described in detail based on the drawings showing its embodiments. (Embodiment 1) Figure 1 is a block diagram showing the configuration of an information processing device 1 according to Embodiment 1 of the present disclosure. In the figure, 1 is an information processing device 1 according to an embodiment of the present disclosure. The information processing device 1 is a computer equipped with a processing unit 11 such as a CPU (Central Processing Unit), and a storage unit 12 is connected to the processing unit 11 via a bus. The storage unit 12 includes, for example, non-volatile memory and volatile memory. The non-volatile memory is a ROM such as an EEPROM (Electrically Erasable Programmable ROM). The non-volatile memory stores a control program necessary for the initial operation of the computer and a simulator program 21 according to this embodiment. The simulator program 21 includes, for example, a transformer operation simulator program (computer program) 21a, a circuit simulator program 21b, a magnetic field analysis simulator program 21c, etc. The processing unit 11 functions as a transformer operation simulator that simulates the operation of the transformer 4 (see Figure 2) at multiple time points by executing the simulator program 21, a circuit simulator that simulates the operation of the primary and secondary circuits of the transformer 4, and a magnetic field analysis simulator that performs magnetic field analysis of the transformer 4 using methods such as the finite element method and boundary element method. The volatile memory is, for example, RAM such as DRAM (Dynamic RAM) or SRAM (Static RAM), and temporarily stores the control program read from the non-volatile memory, the simulator program 21, or various data generated by the processing of the processing unit 11 when the processing unit 11 performs its calculations.

[0013] The memory unit 12 also stores an analysis model 12a representing the two-dimensional or three-dimensional shape and electromagnetic characteristics of the core 41 and windings 42 (see Figure 2) that constitute the transformer 4, a circuit model representing the circuit configuration of the primary and secondary circuits of the transformer 4, and the like.

[0014] Figure 2 is a schematic diagram showing a single-phase transformer 4, and Figure 3 is a schematic diagram showing the configuration of an electrical circuit including the transformer 4. The transformer 4 to be simulated is, for example, a single-phase transformer and comprises an E-type core 41, a primary winding 42p wound around the core 41, and a secondary winding 42s. The analysis model 12a includes, for example, a three-dimensional shape model such as three-dimensional CAD data representing the shapes of the core 41 and the multiple windings 42 that constitute the transformer 4, and material properties of each part that constitutes the three-dimensional shape model. Material properties include magnetization properties, electrical properties, mechanical properties, thermal properties, iron loss properties, etc. Electrical properties include conductivity, relative permittivity, etc.

[0015] The primary circuit to be simulated comprises an AC power supply, resistor, and inductor connected in series with the primary winding 42p, as shown in Figure 3. The secondary circuit comprises a resistor, inductor, and load connected in series with the secondary winding 42s. The memory unit 12 stores circuit models representing multiple circuit elements constituting the primary and secondary circuits of the transformer 4, as well as the connection state and characteristics of each circuit element. The circuit shown in Figure 3 satisfies equations (1) and (2) below. In Figure 3, the variables enclosed by dashed lines are known values ​​given by the circuit simulator. The information processing device 1 determines the current and flux linkage of the transformer 4 by solving the voltage equation of the transformer 4 in this state using iterative calculations such as the Newton-Raphson method.

[0016]

number

[0017] Furthermore, the memory unit 12 stores the first LUT 12b and the second LUT 12c as a characteristic database for efficiently simulating the operation of the transformer 4. The first and second LUTs 12b and 12c are created in the preliminary stage before simulating the operation of the transformer 4. Details of the first and second LUTs 12b and 12c will be described later.

[0018] The storage unit 12 may include a read-only disk drive such as a hard disk drive or solid-state drive, and a CD-ROM drive or other device capable of reading data from a portable recording medium 2. The simulator program 21 or transformer operation simulator program 21a according to this embodiment is recorded in a computer-readable manner on a recording medium 2 such as a portable media like a CD (Compact Disc)-ROM, DVD (Digital Versatile Disc)-ROM, or BD (Blu-ray Disc) (registered trademark). Note that an optical disc is just one example of a recording medium 2, and the simulator program 21 or transformer operation simulator program 21a may also be recorded in a computer-readable manner on a flexible disc, magneto-optical disc, external hard disk, semiconductor memory, etc. The processing unit 11 reads the simulator program 21 or transformer operation simulator program 21a from the recording medium 2 and stores it in a hard disk drive, solid-state drive, etc. The processing unit 11 makes the computer function as an information processing device 1 by executing the simulator program 21 recorded on the recording medium 2 or the simulator program 21 stored in the storage unit 12.

[0019] Furthermore, as shown in Figure 1, the information processing device 1 is equipped with an input device 13 such as a keyboard or mouse, and an output device 14 such as a liquid crystal display or CRT display, and accepts operations from the user, such as data input.

[0020] Furthermore, the information processing device 1 may be equipped with a communication interface 15, and may download the simulator program 21 or transformer operation simulator program 21a related to this disclosure from an external server computer 3 connected to the communication interface 15, and execute processing in the processing unit 11.

[0021] FIG. 4 is a conceptual diagram showing an overview of the coupled analysis executed by the information processing apparatus 1. First, before simulating the operation of the transformer 4, the information processing apparatus 1 calculates various characteristics of the transformer 4 by magnetic field analysis based on an analysis model 12a such as a finite element method model. For example, the processing unit 11 creates a first LUT 12b associating the current in the primary winding 42p, the current in the secondary winding 42s, and the linked magnetic flux generated in the primary winding 42p as characteristics of the transformer 4. Further, the processing unit 11 creates a second LUT 12c associating the current in the primary winding 42p, the current in the secondary winding 42s, and the linked magnetic flux generated in the secondary winding 42s. Hereinafter, as appropriate, the current in the primary winding 42p is referred to as the primary current, the current in the secondary winding 42s is referred to as the secondary current, the linked magnetic flux generated in the primary winding 42p is referred to as the primary magnetic flux, and the linked magnetic flux generated in the secondary winding 42s is referred to as the secondary magnetic flux.

[0022] Then, the information processing apparatus 1 couples a transformer operation simulator and a circuit simulator to simulate the operation of the transformer 4. The circuit simulator delivers the voltages of the primary winding 42p and the secondary winding 42s of the transformer 4 to the transformer operation simulator. The transformer operation simulator obtains the linked magnetic flux and current of each winding 42 by referring to the first LUT 12b and the second LUT 12c, and returns the simulation result to the circuit simulator. Hereinafter, the operation of the transformer 4 can be simulated by repeatedly executing the same process.

[0023] Hereinafter, the problems in creating the first and second LUTs 12b and 12c, the method of creating the first and second LUTs 12b and 12c according to the present embodiment, and the operation simulation procedure of the transformer 4 will be described in order.

[0024] <Problems in creating LUT> The primary magnetic flux and the secondary magnetic flux can be expressed as functions of the primary current and the secondary current as shown in the following equations (3) and (4). In order to improve the calculation speed of the linked magnetic flux, the information processing apparatus 1 obtains the linked magnetic flux for a plurality of current values in advance by magnetic field analysis, and creates the first and second LUTs 12b and 12c associating the primary current and the secondary current with the linked magnetic flux.

[0025]

number

[0026] Figure 5 is a conceptual diagram showing the first and second LUTs 12b and 12c, which have not been normalized or rotated. Figure 5A shows the first LUT 12b, which associates the primary and secondary currents with the primary magnetic flux, and Figure 5B shows the second LUT 12c, which associates the primary and secondary currents with the secondary magnetic flux. The LUTs shown in Figure 5 are simplified and intended to help understand the concept. The information processing device 1 can read out the primary and secondary magnetic fluxes using the primary and secondary currents as keys. The LUT shown in Figure 5 is a table of primary and secondary magnetic fluxes for a total of nine calculation points, three for each of the primary and secondary currents. Ideally, the primary and secondary currents satisfy the following equation (5), so the numerical range of the primary and secondary currents stored in the first and second LUTs 12b and 12c should be determined by the ratio of the primary winding 42p and the secondary winding 42s. If the primary winding 42p has 320 turns and the secondary winding 42s has 32 turns, and the numerical range of the secondary current is set to -100 to 100, then the numerical range of the primary current should be 32 / 320 × (-100) to 32 / 320 × 100, which is -10 to 10. Also, in the example shown in Figure 5, the resolution (current step) of the primary current is 10, and the resolution of the secondary current is 100.

[0027]

number

[0028] Next, we will explain the resolution of the primary and secondary currents in the first and second LUTs 12b and 12c. Figure 6 is a graph showing the flux linkage of the primary winding 42p, and Figure 7 is a graph showing the flux linkage of the secondary winding 42s. Figure 6A is a graph showing the relationship between the primary current and the primary flux, and Figure 6B is a graph showing the relationship between the secondary current and the primary flux. Note that Figure 6A graphs the flux linkage for multiple different secondary currents, and Figure 6B graphs the flux linkage for multiple different primary currents. Figure 7A is a graph showing the relationship between the primary current and the secondary flux, and Figure 7B is a graph showing the relationship between the secondary current and the secondary flux. Note that Figure 7A graphs the flux linkage for multiple different secondary currents, and Figure 7B graphs the flux linkage for multiple different primary currents. In the examples shown in Figures 6 and 7, the numerical ranges of the primary current and secondary current are -500 to 500 (A) and -5000 to 5000 (A), respectively.

[0029] Figure 8 is a conceptual diagram showing the resolution of the primary current and the error in the flux linkage. The vertical axis represents the primary flux, and the horizontal axis represents the primary current. The graph drawn with large circles represents the flux linkage plotted with a primary current step of 1 (A), and the graph drawn with small circles represents the flux linkage plotted with a primary current step of 0.2 (A). As shown in Figure 8, the flux linkage changes sharply within the numerical range enclosed by the rectangular frame. It can be seen that in the range where the primary flux changes significantly with respect to the primary current, the error in the primary flux will increase unless the step size of the primary current is made smaller.

[0030] Figure 9 is a conceptual diagram showing the region where the flux linkage changes sharply with respect to the current in the primary winding 42p. Looking at Figure 8, it appears that the flux linkage changes sharply in a limited region, but in reality, as shown in Figure 9, the numerical range of the primary current over which the current step size must be finer changes depending on the magnitude of the secondary current. Therefore, in order to reduce the error in the primary flux regardless of the secondary current, the current step size must be finer over the entire range of the primary current. Up to this point, we have shown the relationship between the primary current and the primary flux, but as shown in Figures 6 and 7, similar relationships exist between the secondary current and the primary flux, the primary current and the secondary flux, and the primary current and the secondary flux. Therefore, it is ultimately necessary to perform magnetic field analysis by finer current step sizes over the entire range of both the primary and secondary currents.

[0031] If the calculation points for the primary and secondary currents are Np and Ns respectively, then all calculation points will be Np × Ns, and the number of calculation points will increase exponentially as Np and Ns increase. When considering the primary and secondary currents of a three-phase system, the number of calculation points will increase exponentially to the sixth power, resulting in an enormous number of calculation points. Therefore, it is desirable to devise methods to avoid large errors while also preventing the number of calculation points from becoming excessively large.

[0032] <Method for creating a LUT according to this embodiment> The lookup table creation method according to this embodiment 1 reduces the number of calculation points for which flux linkage should be calculated by normalizing and rotating the primary and secondary currents.

[0033] <Normalization> Normalization is a process to align the numerical ranges of the primary and secondary currents, as well as the product of the current and the number of turns expressed in equation (5). The magnetic flux linked to the core 41, which is the iron core, is a function of the product of the number of turns of the winding 42 and the current, so the linked flux can be expressed as shown in equations (6) and (7) below. In other words, the primary current Ip and secondary current Is associated with the linked flux in the first LUT 12b and the second LUT 12c can be expressed as np × Ip and ns × Is, respectively. By substituting the primary current Ip and secondary current Is with np × Ip and ns × Is, the range of numerical values ​​to be considered can be made consistent. This means that the number of turns has also been incorporated as a variable of the LUT.

[0034]

number

[0035] There are several methods for normalizing the primary current Ip and secondary current Is. In any of these methods, the numerical range of the currents to be considered can be standardized. (Method 1)np·Ip,ns·Is (Method 2) Ip,(ns / np)·Is (Method 3) Ip / ns, Is / np (Method 4)(np / ns)·Ip,Is

[0036] Assuming the numerical ranges for the primary and secondary currents are -500 to 500 (A) and -5000 to 5000 (A), respectively, and with np = 320 and ns = 32, the normalized numerical ranges for each current are as follows: (Method 1)-500×320~500×320,-5000×32~5000×32 (Method 2)-500~500,-5000×32 / 320~5000×32 / 320 (Method 3)-500 / 32~500 / 32,-5000 / 320~5000 / 320 (Method 4)-500×320 / 32~500×320 / 32,-5000~5000

[0037] In any of the normalization methods 1 to 4, the numerical ranges of the normalized primary and secondary currents are consistent. The following explanation uses an example of normalization using Method 2.

[0038] <Axis rotation> Axis rotation is a process of rotating the component axes of the primary and secondary currents so as to broaden the range in which the change in flux linkage for the primary and secondary currents is gradual, and narrow the range in which the change in flux linkage is steep. The primary and secondary fluxes can be considered as functions of Ip and (ns / np)·Is, but from Figure 6, it can be inferred that the flux linkage becomes a constant value by adding Ip and (ns / np)·Is. Therefore, the primary and secondary currents are rotated axially as shown in equations (8) and (9) below. Hereafter, the two currents obtained by normalizing and rotating the primary and secondary currents will be called the first current and the second current.

[0039]

number

[0040] Note that while equations (8) and (9) above show the primary and secondary currents normalized by method 2 rotated along an axis, the primary and secondary currents normalized by another method may be added together to obtain the first current, and the result of subtracting these two currents may be obtained as the second current.

[0041] Figure 10 is a graph showing the primary magnetic flux for normalized and axially rotated currents, and Figure 11 is a graph showing the secondary magnetic flux for normalized and axially rotated currents.

[0042] Figure 10A is a graph showing the primary magnetic flux with respect to the first current, and it remains almost constant regardless of the value of the first current. Therefore, there is no need to fine-tune the increment of the first current used to calculate the primary magnetic flux.

[0043] On the other hand, Figure 10B is a graph showing the primary magnetic flux for the second current, and the primary magnetic flux changes sharply when the second current is around 0(A). Therefore, it can be seen that the step size for the second current used to calculate the primary magnetic flux should be set finely around 0(A) and coarsely in other numerical ranges. Note that in Figure 10B, multiple graphs are drawn for different first currents, but since they are all graphs of approximately the same shape, they appear to be superimposed as a single graph.

[0044] Thus, when creating the first LUT12b for primary and secondary currents that have not been normalized or rotated, it is necessary to perform magnetic field analysis on the primary flux with fine current step sizes across the entire range of values ​​that the primary and secondary currents can take. However, when creating the first LUT12b for normalized and rotated primary and secondary currents, it is sufficient to perform magnetic field analysis on the primary flux with coarse current step sizes across the entire range of values ​​for the primary current, fine step sizes only around 0 for the secondary current, and coarse step sizes for other numerical ranges. The same applies to the secondary flux.

[0045] Figure 11A is a graph showing the secondary magnetic flux with respect to the first current, and it remains almost constant regardless of the value of the first current. Therefore, there is no need to fine-tune the increment of the first current when calculating the secondary magnetic flux.

[0046] On the other hand, Figure 11B is a graph showing the secondary magnetic flux for the second current, and the secondary magnetic flux changes sharply when the second current is around 0(A). Therefore, it can be seen that the step size for the second current used to calculate the secondary magnetic flux should be set finely around 0(A) and coarsely in other numerical ranges. Note that in Figure 11B, multiple graphs are drawn for different first currents, but since they are all graphs of approximately the same shape, they appear to be superimposed as a single graph.

[0047] Thus, when creating a second LUT12c for primary and secondary currents that have not been normalized or rotated, it is necessary to perform magnetic field analysis on the secondary flux with fine current steps across the entire range of values ​​that the primary and secondary currents can take. However, when creating a second LUT12c for normalized and rotated first and second currents, it is sufficient to perform magnetic field analysis on the secondary flux with coarse current steps across the entire range for the first current, fine steps only around 0 for the second current, and coarse steps for other numerical ranges.

[0048] Figure 12 is a flowchart showing the processing procedure for creating the first and second LUTs 12b and 12c according to Embodiment 1. The processing unit 11 of the information processing device 1 executes the following processing according to the transformer operation simulator program 21a stored in the memory unit 12. First, the processing unit 11 accepts the selection of the analysis model 12a and drive circuit model of the transformer 4 to be simulated, and various other settings, from the input device 13 (step S111). Here, the processing unit 11 may accept the number of turns of the primary winding 42p and secondary winding 42s of the transformer 4, the numerical range of the primary current or secondary current, or the upper and lower limits. The processing unit 11 may also accept the resolution of the primary current or secondary current, i.e., the step size ΔIp or ΔIs of the current value.

[0049] Next, the processing unit 11 normalizes the primary and secondary currents (step S112) and rotates the shaft (step S113). For example, the processing unit 11 normalizes the primary and secondary currents and rotates the shaft according to the above equations (8) and (9).

[0050] Next, the processing unit 11 determines the numerical range and resolution of the normalized and axially rotated first and second currents (step S114). For example, the processing unit 11 may determine the numerical range of the first current based on the numerical range of the primary or secondary current received in step S111 and the above formula (8). Similarly, the numerical range of the second current may be determined based on the numerical range of the primary or secondary current and the above formula (9). For example, if the numerical ranges of the normalized primary and secondary currents are -500 to 500, then the numerical ranges of the first and second currents will be -1000 to 1000. Furthermore, based on the resolution of the primary or secondary current received in step S111, the processing unit 11 determines the reference resolution (hereinafter referred to as the reference resolution) for the first and second currents using equations (8) and (9) above. The processing unit 11 then sets a resolution coarser than the reference resolution for the first current. The processing unit 11 also sets a resolution coarser than the reference resolution for the second current in the numerical range excluding the vicinity of 0(A). For the numerical range of the second current near 0(A), the processing unit 11 sets the reference resolution or a resolution higher than the reference resolution. Note that this method of determining the resolution is just one example and is not particularly limited.

[0051] Next, the processing unit 11 performs a magnetic field analysis such as the finite element method based on the numerical range and resolution of the first and second currents determined in step S114 (step S115), and calculates the primary and secondary magnetic fluxes (step S116).

[0052] Next, the processing unit 11 creates a first LUT 12b that associates the first current, the second current, and the primary magnetic flux calculated in step S114, and a second LUT 12c that associates the first current, the second current, and the secondary magnetic flux (step S117), and then completes the processing.

[0053] <Transformer operation simulation> Figure 13 is a flowchart showing the processing procedure for transformer operation simulation. The processing unit 11 sets initial values ​​such as the voltage and current applied to the winding 42 (step S131). Next, the processing unit 11 calculates the voltage to be applied to the winding 42 in the next simulation step based on the current and flux linkage of the winding 42 calculated in the previous simulation step (step S132). The processing in step S132 is performed by the circuit simulator (see Figure 4), and the simulation result voltage is provided to the transformer operation simulator.

[0054] Next, the processing unit 11 simulates the operation of the transformer 4 based on the voltage applied to the transformer 4, the currents in each winding 42 calculated in previous simulation steps, the flux linkage in each winding 42, etc., and calculates the current flowing through each winding 42 and the flux linkage (step S133). The processing unit 11 obtains the primary and secondary fluxes by referring to the first LUT 12b and the second LUT 12c using the primary and secondary currents as keys, and obtains the primary and secondary currents, primary fluxes, and secondary fluxes in the current simulation step by solving the voltage equations of the transformer 4 etc. by iterative calculations such as the Newton-Raphson method. The processing in step S133 is performed by the transformer operation simulator (see Figure 4), and the simulation results of the winding 42 currents and flux linkage are passed to the circuit simulator.

[0055] Next, the processing unit 11 determines whether or not the simulation termination conditions are met (step S134). For example, if a predetermined number of simulation steps corresponding to a predetermined real time have been executed, the processing unit 11 terminates the simulation. If it is determined that the simulation termination conditions are not met (step S134: NO), the processing unit 11 returns to step S132 and repeatedly executes the processes of steps S132 and S133. If it is determined that the simulation termination conditions have been met (step S134: YES), the processing unit 11 terminates the process.

[0056] As described above, the computer program, lookup table creation method, and information processing device 1 according to this embodiment 1 can reduce the creation load of the first and second LUTs 12b and 12c for determining the flux linkage of the transformer 4.

[0057] Specifically, by normalizing and axially rotating the primary and secondary currents, the numerical region in which the flux linkage with respect to the current changes sharply can be narrowed down to around 0(A), as shown in Figures 10 and 11. Therefore, for the normalized and axially rotated first and second currents near 0(A), the magnetic field analysis of the flux linkage can be performed with fine current step sizes, while for other current numerical regions, the magnetic field analysis of the flux linkage can be performed with coarse current step sizes. Thus, the number of calculation points for which magnetic field analysis must be performed to create the first and second LUTs 12b and 12c can be reduced, thereby reducing the workload for creating the LUTs.

[0058] The primary and secondary currents can be normalized by a simple process of multiplying and subtracting the number of turns of the primary winding 42p and the secondary winding 42s from the primary and secondary currents. By normalizing the currents, it becomes easier to set the current step sizes for the first and second currents necessary to create the first and second LUTs 12b and 12c.

[0059] Furthermore, by performing a simple axis rotation operation involving the addition and subtraction of the normalized first and second currents, the numerical region in which the change in flux linkage with respect to the current becomes steep can be narrowed down to around 0 (A).

[0060] (Embodiment 2) The information processing device 1 according to Embodiment 2 differs from that of Embodiment 1 in that the configuration of the LUT can be simplified by normalizing and rotating the flux linkage. The other configurations and processes of the information processing device 1 are the same as those of the information processing device 1 according to Embodiment 1, so the same reference numerals are used for the same parts, and detailed explanations are omitted.

[0061] Figure 14 is a flowchart showing the processing procedure for creating the first and second LUTs 12b and 12c according to Embodiment 2. The processing unit 11 performs processing related to the normalization of the primary and secondary currents, axis rotation, and magnetic field analysis, similar to Embodiment 1 (steps S211 to S216).

[0062] Next, the processing unit 11 normalizes the primary and secondary magnetic fluxes (step S217) and rotates the axis (step S218). For example, the processing unit 11 normalizes the primary and secondary magnetic fluxes and rotates the axis according to the following equations (10) and (11). Hereinafter, the two magnetic fluxes obtained by normalizing the primary and secondary magnetic fluxes and rotating the axis will be referred to as the first magnetic flux and the second magnetic flux.

[0063]

number

[0064] In (10) and (11) above, the first and second magnetic fluxes are calculated by adding and subtracting the primary and secondary magnetic fluxes, which have been normalized by multiplying the primary magnetic flux by ns / np. However, the primary and secondary magnetic fluxes may be normalized by other methods. For example, similar to the normalization of the primary and secondary currents, the primary and secondary magnetic fluxes may be normalized by the following method, and the sum of the normalized primary and secondary magnetic fluxes may be taken as the first magnetic flux, and the subtraction of the normalized primary and secondary magnetic fluxes may be taken as the second magnetic flux. (Method 1) ns·Φp,np·Φs (Method 2)Φp,(np / ns)·Φs (Method 3) Φp / np, Φs / ns (Method 4)(ns / np)·Φp,Φs

[0065] Figure 15 is a graph representing the normalized and axially rotated first magnetic flux, and Figure 16 is a graph representing the normalized and axially rotated second magnetic flux. Figure 15A is a graph showing the first magnetic flux for the first current, and Figure 15B is a graph showing the first magnetic flux for the second current. In both cases, the values ​​are approximately constant regardless of the value of the first current. Therefore, it is not necessary to make the increments of the first current finer when calculating the first and second magnetic fluxes. Note that in Figures 15A and 15B, multiple graphs are drawn for different second and first currents, but since they are all graphs of approximately the same shape, they appear to be superimposed as a single graph.

[0066] On the other hand, Figure 16A is a graph showing the second magnetic flux for the first current, and it is almost constant regardless of the value of the first current. Therefore, there is no need to make the increment of the first current finer when calculating the second magnetic flux. Figure 16B is a graph showing the second magnetic flux for the second current, and the primary magnetic flux changes sharply when the second current is around 0(A). Therefore, it can be seen that the increment of the second current when calculating the second magnetic flux should be fine around 0(A) and coarse in other numerical ranges. Note that in Figure 16B, multiple graphs for different first currents are drawn, but since they are all graphs of approximately the same shape, they appear to be superimposed as a single graph.

[0067] Next, the processing unit 11 creates a first LUT 12b that associates the first current, the second current, and the first magnetic flux, and a second LUT 12c that associates the first current, the second current, and the second magnetic flux (step S219), and then completes the processing.

[0068] In this way, by normalizing and axially rotating the primary and secondary magnetic fluxes, the relationship between the first and second currents and the magnetic flux density can be simplified, as shown in Figures 15 and 16. Specifically, the normalized and axially rotated first magnetic flux becomes approximately constant, about 0 (A), regardless of the values ​​of the first and second currents, thereby reducing the amount of data in the first LUT12b.

[0069] As described above, the computer program, lookup table creation method, and information processing device 1 according to this second embodiment can reduce the creation load of the first and second LUTs 12b and 12c for determining the flux linkage of an electromagnetic device having a winding 42, and can reduce the amount of data for the first and second LUTs 12b and 12c.

[0070] (Embodiment 3) The information processing device 1 according to Embodiment 3 differs from Embodiments 1 and 2 in that the electromagnetic device to be analyzed is a three-phase transformer. The other configurations and processes of the information processing device 1 are the same as those of the information processing device 1 according to Embodiment 1, so the same reference numerals are used for the same parts, and detailed explanations are omitted.

[0071] Figure 17 is a schematic diagram showing a three-phase transformer. The transformer 304 to be simulated according to Embodiment 3 is, for example, a three-phase transformer and comprises U-phase, V-phase, and W-phase cores 341, a primary winding 42up and a secondary winding 42us for the U-phase wound around each core 341, a primary winding 42vp and a secondary winding 42vs for the V-phase, and a primary winding 42wp and a secondary winding 42ws for the W-phase.

[0072] The processing unit 11 of the information processing device 1 according to Embodiment 3 converts the component axes of the multiple currents flowing through each winding 42 so as to widen the numerical range in which the change in the magnetic flux linkage of the U-phase, V-phase, or W-phase with respect to the current flowing through each winding 42 is gradual, and narrow the numerical range in which the change in magnetic flux linkage is steep. For example, the processing unit 11 normalizes and converts the axes of the primary and secondary currents of the U-phase, V-phase, and W-phase, respectively, using the following equations (12-1) to (12-6).

[0073]

number

[0074] Furthermore, the processing unit 11 creates a first LUT 12b by associating the normalized and axis-shifted first to sixth currents with the first magnetic flux. Similarly, the processing unit 11 creates second to sixth LUTs by associating the normalized and axis-shifted first to sixth currents with the second to sixth magnetic fluxes. The first to sixth magnetic fluxes are the magnetic fluxes obtained by normalizing and axis-shifting the primary and secondary magnetic fluxes of the U-phase, V-phase, and W-phase, respectively. For example, the first to sixth magnetic fluxes are expressed by the following equations (13-1) to (13-6).

[0075]

number

[0076] Figure 18 (Figures 18A to 18C) is a graph showing the normalized and axially rotated first to third magnetic fluxes for the normalized and axially rotated first current, and Figure 19 (Figures 19A to 19C) is a graph showing the normalized and axially rotated first to third magnetic fluxes for the normalized and axially rotated second current.

[0077] By normalizing the current and magnetic flux density and transforming the component axes in this way, as shown in Figure 18A, the region in which the first magnetic flux changes sharply with respect to the first current can be narrowed to approximately 0 (A). In other numerical ranges as well, the change in the first magnetic flux with respect to the first current can be made approximately linear. The same applies to Figure 19B.

[0078] Furthermore, as shown in Figure 18C, the second magnetic flux with respect to the first current is approximately constant. Similarly, as shown in Figure 19C, the third magnetic flux with respect to the second current is approximately constant.

[0079] Furthermore, as shown in Figure 18B, the change in the third magnetic flux with respect to the first current can be constant near 0(A) and approximately linear in other numerical ranges. The same applies to the first magnetic flux with respect to the second current, as shown in Figure 19A.

[0080] In this way, for the three-phase transformer 4 as well, the change in flux linkage with respect to the normalized and component axis-transformed current can be made to converge to around 0 (A), and a linear increasing / decreasing trend can be observed in other numerical ranges as well, thereby reducing the number of calculation points required to create the LUT.

[0081] According to Embodiment 3, by normalizing the current and converting the axis, the manufacturing load of the first to sixth LUTs can be reduced, similar to Embodiment 1. Also, similar to Embodiment 2, by normalizing the flux linkage and converting the axis, the configuration of the first to sixth LUTs can be simplified.

[0082] In this third embodiment, an example was described in which the flux linkage is normalized and axis-shifted along with the current. However, it is also possible to configure the system to normalize and axis-shift only the current. Similar to the first embodiment, the number of calculation points required to create the LUT can be reduced.

[0083] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims, not in the sense described above, and all modifications are intended to be in the sense and scope equivalent to the claims. [Explanation of symbols]

[0084] 1. Information Processing Device 2 Recording media 3 Server Computers 4. Transformer 11 Processing Section 12 Storage section 12a Analysis Model 12b 1st LUT 12c 2nd LUT 13 Input device 14 Output device 15 Communication Interfaces 21 Simulator Program 21a Transformer Operation Simulator Program 21b Circuit simulator program 21c Magnetic Field Analysis Simulator Program 41 cores 42 windings 42p Primary winding 42s secondary winding 42up U-phase primary winding 42vp V phase primary winding 42wp W-phase primary winding 42us U-phase secondary winding 42vs V-phase secondary winding 42ws W-phase secondary winding

Claims

1. A computer program that causes a computer to perform a process of creating a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the said electromagnetic device, The component axes of the multiple currents flowing through each winding are transformed so that the range of values ​​in which the change in flux linkage with respect to the currents flowing through each winding is gradual is broadened, and the range of values ​​in which the change in flux linkage is steep is narrowed. For multiple currents whose component axes have been transformed, perform a magnetic field analysis based on the aforementioned analysis model. The flux linkage calculated by the aforementioned magnetic field analysis is correlated with the current whose component axes have been transformed. A computer program that causes the computer to perform a process.

2. In order to standardize the numerical range of the currents flowing through the aforementioned multiple windings, the multiple currents flowing through each winding are normalized. The computer program according to claim 1.

3. The multiple currents flowing through each winding are normalized by multiplying or dividing the currents flowing through each winding by the number of turns in each winding. The computer program according to claim 2.

4. By rotating the component axes of the multiple currents, the component axes of the multiple currents are transformed. The computer program according to claim 1.

5. The electromagnetic device comprises a primary winding and a secondary winding. The first current, which has been converted to a different component axis, is calculated by adding the currents of the primary and secondary windings, and the second current, which has been converted to a different component axis, is calculated by subtracting the currents of the primary and secondary windings. The computer program according to claim 4.

6. The electromagnetic device comprises a primary winding and a secondary winding. The currents in the primary and secondary windings are normalized and the shaft rotated according to the following equations (1-1) and (1-2). The computer program according to claim 1. [Math 1]

7. The component axis of the flux linkage for each winding is transformed so that the range of values ​​in which the change in flux linkage for the current flowing through each of the aforementioned windings is gradual is broadened, and the range of values ​​in which the change in flux linkage is steep is narrowed. The computer program according to claim 1.

8. The number of turns in each winding is multiplied or divided by the flux linkage of each winding to normalize the multiple flux linkages. The computer program according to claim 7.

9. The flux linkage of the primary and secondary windings is normalized and the component axes are transformed using the following equations (2-1) and (2-2). The computer program according to claim 6. [Math 2]

10. The operation of the electromagnetic device is simulated by referring to the lookup table using the current flowing through the winding. A computer program according to any one of claims 1 to 9.

11. A method for creating a lookup table in which a computer creates a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the electromagnetic device, The aforementioned computer, The component axes of the multiple currents flowing through each winding are transformed so that the range of values ​​in which the change in flux linkage with respect to the currents flowing through each winding is gradual is broadened, and the range of values ​​in which the change in flux linkage is steep is narrowed. For multiple currents whose component axes have been transformed, perform a magnetic field analysis based on the aforementioned analysis model. The flux linkage calculated by the aforementioned magnetic field analysis is correlated with the current whose component axes have been transformed. How to create a lookup table.

12. An information processing device comprising a processing unit that performs a process to create a lookup table for simulating the operation of an electromagnetic device having multiple windings, based on an analysis model of the electromagnetic device, The aforementioned processing unit, The component axes of the multiple currents flowing through each winding are transformed so that the range of values ​​in which the change in flux linkage with respect to the currents flowing through each winding is gradual is broadened, and the range of values ​​in which the change in flux linkage is steep is narrowed. For multiple currents whose component axes have been transformed, perform a magnetic field analysis based on the aforementioned analysis model. The flux linkage calculated by the aforementioned magnetic field analysis is correlated with the current whose component axes have been transformed. An information processing device that performs processing.

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