Information processing device, information processing method, and information processing program

Abstract

The present invention analyzes temperature distribution of a circuit including an electronic component. In the present invention, a heat equivalence circuit of each of constituent elements of a series circuit is modeled as a device having a terminal for connecting to the heat equivalence circuit of another constituent element of the series circuit, and the heat equivalence circuits modeled by a first modeling process are connected to each other via the terminal to model the heat equivalence circuit of the series circuit.

Description

Information processing device, information processing method, and information processing program

[0001] The present invention relates to an information processing device, an information processing method, and an information processing program.

[0002] In recent years, the electronics of vehicles has been advancing. As a result, the amount of heat generated by electronic components and wiring harnesses mounted on vehicles has increased, making design based on thermal analysis necessary (see, for example, Non-Patent Document 1). For example, Patent Document 1 discloses a method for analyzing the temperature distribution of a wiring harness.

[0003] Japanese Patent Application Laid-Open No. 2018-128426

[0004] Keiji Mashimo and three others, "Thermal Analysis Technology for Automotive Parts," [online], July 2002, Furukawa Electric Review No. 110, [Retrieved September 28, 2023], Internet: https: / / www.furukawa.co.jp / jiho / fj110 / fj110_16.pdf

[0005] Patent Document 1 does not disclose a method for analyzing the temperature distribution of a circuit including electronic components such as fuses and contactors.

[0006] Therefore, an object of the present invention is to analyze the temperature distribution in a circuit including electronic components.

[0007] In order to solve the above problem, an information processing device according to one embodiment of the present invention is an information processing device for analyzing the temperature distribution of a series circuit including electronic components, and has: a first modeling unit that models the thermal equivalent circuit of each of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of other components of the series circuit; and a second modeling unit that connects the thermal equivalent circuits modeled by the first modeling unit to each other via the terminals, and models the thermal equivalent circuit of the series circuit.

[0008] An information processing method according to one embodiment of the present invention is an information processing method executed by a computer for analyzing the temperature distribution of a series circuit including electronic components, and includes a first modeling step of modeling the thermal equivalent circuit of each of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of other components of the series circuit, and a second modeling step of connecting the thermal equivalent circuits modeled by the first modeling unit to each other via the terminals and modeling the thermal equivalent circuit of the series circuit.

[0009] An information processing program according to one embodiment of the present invention causes a computer to execute the above-described analysis method.

[0010] According to the present invention, it is possible to analyze the temperature distribution of a circuit including electronic components.

[0011] 1 is a diagram illustrating an analysis device 100 according to an embodiment of the present invention. FIG. 1 is a diagram illustrating an example of a series circuit SC. FIG. 2 is a diagram illustrating a control unit 110. FIG. 3 is a diagram illustrating an example of a processing operation in the control unit 110. FIG. 4 is a diagram illustrating an example of a reference thermal equivalent circuit of a bus bar when the bus bar is not housed in a circuit case CC. FIG. 5 is a diagram illustrating an example of a reference thermal equivalent circuit of a bus bar when the bus bar is housed in a circuit case CC. FIG. 6 is a diagram illustrating an example of a reference thermal equivalent circuit of a bus bar when the bus bar is not housed in a circuit case CC. FIG. 7 is a diagram illustrating an example of a reference thermal equivalent circuit of a bus bar when the bus bar is housed in a circuit case CC. FIG. 8 is a diagram illustrating an example of a reference thermal equivalent circuit of an electric wire when the electric wire is not housed in a circuit case CC. FIG. 9 is a diagram illustrating an example of a reference thermal equivalent circuit of an electric wire when the electric wire is housed in a circuit case CC. FIG. 10 is a diagram illustrating an example of a reference thermal equivalent circuit of an electric wire when the electric wire is not housed in a circuit case CC. FIG. 11 is a diagram illustrating an example of a thermal equivalent circuit of an electric wire when the electric wire is housed in a circuit case CC. 22 is a diagram showing an example of a thermal equivalent circuit of a fuse when the fuse is accommodated in a circuit case CC. FIG. 23 is a diagram showing an example of a thermal equivalent circuit of a fuse when the fuse is not accommodated in a circuit case CC. FIG. 24 is a diagram showing an example of a thermal equivalent circuit of a contactor when the contactor is not accommodated in a circuit case CC. FIG. 25 is a diagram showing an example of a thermal equivalent circuit of a contactor when the contactor is accommodated in a circuit case CC. FIG. 26 is a diagram showing an example of a thermal equivalent circuit of a series circuit SC in the example of the series circuit SC shown in FIG. 2. FIG. 27 is a diagram showing an example of a reference thermal equivalent circuit of a bus bar when the bus bar is not accommodated in a circuit case CC and is cooled. FIG. 28 is a diagram showing an example of a thermal equivalent circuit of a series circuit SC in the example of the series circuit SC shown in FIG. 2. FIG. 29 is a diagram showing an example of a thermal equivalent circuit of a series circuit SC in the example of the series circuit SC in which the cooling order is changed from that of FIG. 22.

[0012] 1 is a diagram showing an analysis device 100 according to one embodiment of the present invention. The analysis device 100 has a control unit 110, an input unit 120, a storage unit 130, and an output unit 140.

[0013] The control unit 110 is an information processing device that processes information from a computer or the like. The input unit 120 is an input device that receives information input from a keyboard, touch panel, camera, microphone, or the like. The storage unit 130 is a storage device that stores information, such as a hard disk drive, solid state drive, or memory. The output unit 140 is an output device that outputs information, such as a display device that displays information, a printing device that outputs printed information, such as a printer, or an audio output device that outputs audio related to information, such as a speaker.

[0014] The analysis device 100 is a device for analyzing the temperature distribution of a series circuit SC in which electronic components, electric wires, and bus bars are connected in series. The electronic components include, for example, a contactor and a fuse, as shown in FIG. 2 . In the example shown in FIG. 2 , electric wires W1 and W2, bus bars B1 to B3, a fuse F, and a contactor C are connected in series in the following order: electric wire W1, bus bar B1, fuse F, bus bar B2, contactor C, bus bar B3, and electric wire W2. In the example shown in FIG. 2 , the bus bars B1 to B3, fuse F, and contactor C of the series circuit SC are housed in a case (circuit case CC). The circuit case CC is, for example, a junction box.

[0015] 3 is a diagram showing the control unit 110. The control unit 110 has an information acquisition processing unit 111, a first modeling unit 112, a second modeling unit 113, a temperature distribution calculation unit 114, and an output processing unit 115.

[0016] The information acquisition processing unit 111 acquires information about the series circuit SC input by the input unit 120. Furthermore, if information about the series circuit SC is stored in the storage unit 130, the information acquisition processing unit 111 acquires the information about the series circuit SC from the storage unit 130. The information about the series circuit SC includes the connection relationships between the components of the series circuit SC, the relationship between the series circuit SC and the circuit case CC, and parameters of each of the components.

[0017] 2 , the information acquisition processing unit 111 acquires information indicating that the electric wires W1 and W2, bus bars B1 to B3, fuse F, and contactor C are connected in series in the following order: bus bar B1, fuse F, bus bar B2, contactor C, bus bar B3, and electric wire W2, as the connection relationship of the components. Furthermore, the information acquisition processing unit 111 acquires information indicating that the electric wires W1 and W2 of the series circuit SC are not housed in the circuit case CC, and the bus bars B1 to B3, fuse F, and contactor C are housed in the circuit case CC, as the relationship between the series circuit SC and the circuit case CC. The information acquisition processing unit 111 then acquires parameters of the electric wires W1 and W2, bus bars B1 to B3, fuse F, and contactor C, as parameters of the components.

[0018] The first modeling unit 112 models the thermal equivalent circuit of each of the components of the series circuit SC as a device having terminals for connection to the thermal equivalent circuits of the other components of the series circuit SC, based on the information about the series circuit SC acquired by the information acquisition processing unit 111. In particular, if at least a portion of the series circuit SC is housed in a circuit case CC, the first modeling unit 112 models the thermal equivalent circuit of each of the components of the series circuit SC as a device having terminals for connection to the thermal equivalent circuits of the other components of the series circuit SC and terminals for connection to the thermal equivalent circuit of the external air or the thermal equivalent circuit of the circuit case CC, and models the thermal equivalent circuit of the circuit case CC as a device having terminals for connection to the thermal equivalent circuits of the components of the series circuit housed in the circuit case CC and terminals for connection to the thermal equivalent circuit of the external air.

[0019] When analyzing the temperature distribution of the series circuit shown in FIG. 2, for example, the first modeling unit 112 models the electric wires W1 and W2 that are not housed in the circuit case CC as a device DW having terminals TW1 and TW2 for connection to other components and a terminal TW3 for connection to the thermal equivalent circuit VSE of the outside air, as shown in FIGS. 12 and 19, and models the thermal equivalent circuits of the bus bars B1 to B3, the fuse F, and the contactor C housed in the circuit case CC as a device DW having terminals TB1, TB2, TF1, TF2 for connection to other components, as shown in FIGS. 2, TC1, TC2, and terminals TB3, TF3, TC3 for connecting to device DCC which models the thermal equivalent circuit of circuit case CC, and circuit case CC is modeled as device DCC which has terminal TCC1 for connecting to devices DB, DF, DC which model the thermal equivalent circuits of bus bars B1 to B3, fuse F, and contactor C which are components housed in circuit case CC, and terminal TCC2 for connecting to the thermal equivalent circuit VSE of the outside air, as shown in FIGS. 9, 15, 18, and 19.

[0020] The second modeling unit 113 connects the thermal equivalent circuits modeled by the first modeling unit 112 to each other via terminals based on information about the series circuit SC acquired by the information acquisition processing unit 111, and models the thermal equivalent circuit of the series circuit SC.

[0021] When analyzing the temperature distribution of the series circuit shown in FIG. 2, for example, the second modeling unit 113 connects the thermal equivalent circuits DW, DB, DF, DC, and DCC modeled by the first modeling unit 112 to each other via terminals TW1 to TW3, TB1 to TB3, TC1 to TC3, TCC1, and TCC2, and models the thermal equivalent circuit of the series circuit SC as shown in FIG. 19.

[0022] The temperature distribution calculation unit 114 calculates the temperature distribution of the series circuit SC based on the thermal equivalent circuit of the series circuit SC modeled by the second modeling unit 113. In this case, for example, at each node of the thermal equivalent circuit of the series circuit SC modeled by the second modeling unit 113, the temperature distribution calculation unit 114 determines a relational equation between the temperature of the node and the temperature of a node adjacent to the node by using Kirchhoff's law, solves this relational equation simultaneously, and calculates the temperature of each node on the series circuit SC, thereby calculating the temperature distribution of the series circuit SC.

[0023] The relationship between the temperature of each node and the temperature of the node adjacent to that node can be determined using Kirchhoff's law if the thermal resistance value included in the thermal equivalent circuit, the value of the heat flow supplied by the current source, and the temperature of the voltage source are known. Therefore, the information acquisition processing unit 111 may acquire the thermal resistance value included in the thermal equivalent circuit of the component, the value of the heat flow supplied by the current source, and the temperature of the voltage source (e.g., the temperature of the external air) as parameters for each component of the series circuit SC. Furthermore, the thermal resistance value included in the thermal equivalent circuit of the component and the value of the heat flow supplied by the current source can also be calculated using parameters such as the size (length and cross-sectional area) of the component, the value of the current flowing through the component, the resistance value of the component, and the thermal conductivity of the component. Therefore, the information acquisition processing unit 111 may acquire, as parameters for each of the components of the series circuit SC, the value of the thermal resistance included in the thermal equivalent circuit of the component, parameters used to calculate the value of the heat flow supplied by the current source (for example, the size of the component (for example, length or cross-sectional area), the value of the current flowing through the component, the resistance value of the component, and the thermal conductivity of the component).

[0024] The output processing unit 115 outputs the temperature distribution of the series circuit SC calculated by the temperature distribution calculation unit 114. At this time, the output processing unit 115 outputs the temperature distribution of the series circuit SC, for example, by displaying the one-dimensional temperature distribution on a display device or by printing the one-dimensional temperature distribution with a printing device.

[0025] As described above, in this embodiment, it is possible to analyze the temperature distribution of a circuit including electronic components. Furthermore, in this embodiment, the temperature distribution of the series circuit SC is calculated by solving simultaneous equations. Therefore, in this embodiment, the temperature distribution calculation unit 114 can be realized using general spreadsheet software.

[0026] FIG. 4 illustrates an example of the processing operation of the control unit 110. The information acquisition processing unit 111 acquires information about the series circuit SC (step S401). The first modeling unit 112, based on the information about the series circuit SC, models each thermal equivalent circuit of the components of the series circuit SC as a device having terminals for connection to the thermal equivalent circuits of other components of the series circuit SC (step S402). The second modeling unit 113, based on the information about the series circuit SC, connects the thermal equivalent circuits modeled by the first modeling unit 112 to each other via terminals to model the thermal equivalent circuit of the series circuit SC (step S403). The temperature distribution calculation unit 114 calculates the temperature distribution of the series circuit SC based on the thermal equivalent circuit of the series circuit SC modeled by the second modeling unit 113 (step S404). The output processing unit 115 outputs the temperature distribution of the series circuit SC calculated by the temperature distribution calculation unit 114 (step S405).

[0027] <First modeling unit 112> When the series circuit SC includes bus bars and electric wires, or when the series circuit SC includes fuses and contactors as electronic components, the first modeling unit 112 models the thermal equivalent circuits of the bus bars, electric wires, fuses, and contactors, which are components of the series circuit SC, as devices having terminals for connecting to the thermal equivalent circuits of other components of the series circuit SC.

[0028] (Modeling of the thermal equivalent circuit of the bus bar) When the series circuit SC includes a bus bar, the first modeling unit 112 first divides the bus bar into a first length (e.g., 1 cm) and models a reference thermal equivalent circuit of the bus bar corresponding to the thermal equivalent circuit of the bus bar for this divided first length.

[0029] 5 and 6 are diagrams showing examples of reference thermal equivalent circuits of a bus bar modeled by the first modeling unit 112. Fig. 5 shows the reference thermal equivalent circuit of a bus bar when the bus bar is not housed in a circuit case CC, and Fig. 6 shows the reference thermal equivalent circuit of a bus bar when the bus bar is housed in a circuit case CC.

[0030] 5 and 6, the node NB corresponds to the bus bar, and in FIG. 5, the node NC corresponds to the circuit case CC.

[0031] 5 and 6 , the current source CSB models the Joule heat generated in the bus bar, and the voltage source VSE models the thermal equivalent circuit of the outside air. The heat flow rate supplied by the current source CSB is the Joule heat generated in the bus bar for the first length and is calculated from the value of the current flowing through the series circuit SC and the resistance value of the bus bar per the first length. The temperature of the voltage source VSE is the temperature of the outside air.

[0032] 5 and 6, thermal resistance RB is the thermal resistance in the heat transfer in the longitudinal direction of the bus bar (the direction in which the bus bar extends). The thermal resistance RB is calculated, for example, by the following formula: Here, LBP is the first length, λB is the thermal conductivity of the bus bar, and SB is the cross-sectional area of ​​the bus bar when the bus bar is cut along a plane perpendicular to the longitudinal direction. In Figures 5 and 6, node NB corresponds to one end of the bus bar of the first length, but node NB may also correspond to the longitudinal center portion of the bus bar of the first length. In this case, the thermal resistance of heat transfer in the longitudinal direction of the bus bar is arranged on both sides of node NB with a thermal resistance value of RB / 2, as shown in Figure 7. Figure 7 shows a reference thermal equivalent circuit of a bus bar when the series circuit SC is not housed in the circuit case CC.

[0033] In FIG. 5 , thermal resistance RBE is the thermal resistance in heat transfer from the bus bar to the external air (air outside the bus bar), and is the combined thermal resistance of convective heat transfer resistance RBE1 from the bus bar to the external air and radiative heat transfer resistance RBE2 from the bus bar to the external air, and is calculated as follows using convective heat transfer resistance RBE1 and radiative heat transfer resistance RBE2: The convection heat transfer resistance RBE1 and the radiation heat transfer resistance RBE2 are calculated by thermal fluid analysis, for example, as follows. Here, SAB is the surface area of ​​the bus bar of the first length, KB is a coefficient determined by the shape and installation conditions of the bus bar of the first length, LRB is a representative length determined by the shape and installation conditions of the bus bar of the first length, TSB is the surface temperature of the bus bar, TE is the temperature of the outside air, σ is the Stefan-Boltzmann constant, FC is a view factor, and f is the emissivity.

[0034] In FIG. 6 , thermal resistance RBC is the thermal resistance in heat transfer from the bus bar to the circuit case CC via the internal air (the air inside the circuit case CC), and is the combined thermal resistance of the convection heat transfer resistance RBC1 from the bus bar to the circuit case CC via the internal air and the radiation heat transfer resistance RBC2 from the bus bar to the circuit case CC via the internal air, and is calculated as follows using the convection heat transfer resistance RBC1 and the radiation heat transfer resistance RBC2: The convective heat transfer resistance RBC1 and the radiative heat transfer resistance RBC2 are calculated by thermal fluid analysis.

[0035] 6, the thermal resistance RC is the thermal resistance of the circuit case CC. The thermal resistance RC is calculated, for example, by the following formula: Here, LC is the longitudinal length of the circuit case CC, λC is the thermal conductivity of the circuit case CC, and SC is the cross-sectional area of ​​the circuit case CC when the circuit case CC is cut along a plane perpendicular to the longitudinal direction.

[0036] In FIG. 6, thermal resistance RCE is the thermal resistance in heat transfer from the circuit case CC to the external air (air outside the circuit case CC), and is the combined thermal resistance of the convection heat transfer resistance RCE1 from the circuit case CC to the external air and the radiation heat transfer resistance RCE2 from the electric wires to the external air, and is calculated as follows using the convection heat transfer resistance RCE1 and the radiation heat transfer resistance RCE2: The convection heat transfer resistance RCE1 and the radiation heat transfer resistance RCE2 are calculated by thermal fluid analysis.

[0037] After the reference thermal equivalent circuit of the bus bar is modeled as described above, the first modeling unit 112 connects the reference thermal equivalent circuit of the bus bar and models the thermal equivalent circuit of the bus bar as a device DB having terminals TB1, TB2, and TB3 for connecting the reference thermal equivalent circuit of the bus bar to the thermal equivalent circuits of other components of the series circuit SC. Figures 8 and 9 are diagrams showing examples of the thermal equivalent circuit of the bus bar modeled by the first modeling unit 112. Figure 8 shows the thermal equivalent circuit of the bus bar when the series circuit SC is not housed in a circuit case CC, and Figure 9 shows the thermal equivalent circuit of the bus bar when the series circuit SC is housed in a circuit case CC. When the series circuit SC is housed in a circuit case CC, the first modeling unit 112 models the thermal equivalent circuit of the circuit case CC as a device DCC having terminals TCC1 and TTC2.

[0038] 8 and 9, terminals TB1 and TB2 of device DB are terminals for connecting to a device that models other components of series circuit SC. In Figures 8 and 9, terminal TB3 of device DB is a terminal for connecting to a voltage source VSE that models the thermal equivalent circuit of the outside air or a device DCC that models the thermal equivalent circuit of the case. In Figure 8, terminal TCC1 of device DCC is a terminal for connecting to a device that models the components housed in circuit case CC among the components of series circuit SC, and terminal TCC2 of device DB is a terminal for connecting to voltage source VSE that models the thermal equivalent circuit of the outside air.

[0039] 8 and 9, in a steady state, Kirchhoff's law holds true between the heat flows flowing into node NB2, that is, the heat flow QB flowing from current source CSB into node NB2 (i.e., Joule heat generated in the bus bar of the first length), the heat flow QNB22 flowing from node NB1 into node NB2 via thermal resistance RB, the heat flow QNB23 flowing from node NB3 into node NB2 via thermal resistance RB, and the heat flow QNB24 flowing from voltage source VSE into node NB2 via thermal resistance RBE or from node NC into node NB2 via thermal resistance RBC, as follows: Therefore, when the bus bar is not housed in the circuit case CC, the following relationship holds between the temperature T1 of node NB1, the temperature T2 of node NB2, the temperature T3 of node NB3, and the temperature TE of the outside air. Furthermore, when the bus bar is housed in a circuit case CC, the following relationship holds between the temperature T1 of node NB1, the temperature T2 of node NB2, the temperature T3 of node NB3, and the temperature TC of the circuit case CC. For other nodes, the relationship between the temperature of the node and the temperature of the node adjacent to the node can be determined by Kirchhoff's law.

[0040] (Modeling of the thermal equivalent circuit of the electric wire) When the series circuit SC includes an electric wire, the first modeling unit 112 first divides the electric wire into pieces of a second length (e.g., 1 cm), and models a reference thermal equivalent circuit of the electric wire corresponding to the thermal equivalent circuit of the electric wire for the divided second length.

[0041] 10 and 11 are diagrams showing examples of reference thermal equivalent circuits of electric wires modeled by the first modeling unit 112. Fig. 10 shows the reference thermal equivalent circuit of the electric wires when the electric wires are not housed in a circuit case CC, and Fig. 11 shows the reference thermal equivalent circuit of the electric wires when the electric wires are housed in a circuit case CC.

[0042] 10 and 11, the electric wire has a conductor and an outer covering (e.g., an insulator) disposed around the conductor to cover the conductor. In FIG. 10 and 11, the node NWC corresponds to the conductor of the electric wire, and the node NWI corresponds to the outer covering of the conductor.

[0043] 10 and 11, the current source CSW is a model of the heat source of the conductor of the electric wire.

[0044] 10 and 11, the thermal resistance RWC is the thermal resistance in the heat transfer in the longitudinal direction of the conductor of the electric wire (the direction in which the conductor extends), and the thermal resistance RWI is the thermal resistance in the heat transfer in the longitudinal direction of the sheath material of the electric wire. The thermal resistances RWC and RWI are calculated, for example, by the following formulas. Here, LWP is the second length, λWC is the thermal conductivity of the conductor of the wire, SWC is the cross-sectional area of ​​the conductor of the wire, λWI is the thermal conductivity of the sheath material of the wire, and SWI is the cross-sectional area of ​​the sheath material of the wire. In Figures 10 and 11, node NWC (NWI) corresponds to one end of the conductor (sheath material) of the second length, but node NWC (NWI) may also correspond to the longitudinal center portion of the conductor (sheath material) of the second length. In this case, the thermal resistance of heat transfer in the longitudinal direction of the conductor (sheath material) is arranged on both sides of node NWC (NWI) with a thermal resistance value of RWC / 2 (RWI / 2).

[0045] 10 and 11, the thermal resistance RWCI is the thermal resistance in the heat transfer from the conductor of the electric wire to the exterior material. The thermal resistance RWCI is calculated by thermal fluid analysis.

[0046] In FIG. 10 , thermal resistance RWIE is the thermal resistance in heat transfer from the sheath material of the electric wire to the external air (air outside the electric wire), and is the combined thermal resistance of convective heat transfer resistance RWIE1 from the sheath material of the electric wire to the external air and radiative heat transfer resistance RWIE2 from the sheath material of the electric wire to the external air, and is calculated as follows using the convective heat transfer resistance RWIE1 and the radiative heat transfer resistance RWIE2: The convection heat transfer resistance RWIE1 and the radiation heat transfer resistance RWIE2 are calculated by thermal fluid analysis.

[0047] In FIG. 11 , thermal resistance RWIC is the thermal resistance in heat transfer from the exterior packaging material of the electric wire to the circuit case CC via the internal air (the air inside the circuit case CC), and is the combined thermal resistance of convection heat transfer resistance RWIC1 from the exterior packaging material of the electric wire to the circuit case CC via the internal air, and radiation heat transfer resistance RWIC2 from the exterior packaging material of the electric wire to the circuit case CC via the internal air, and is calculated as follows from the convection heat transfer resistance RWIC1 and the radiation heat transfer resistance RWIC2: In addition, the convection heat transfer resistance RWIC1 and the radiation heat transfer resistance RWIC2 are calculated by thermal fluid analysis.

[0048] After the reference thermal equivalent circuit of the electric wire is modeled as described above, the first modeling unit 112 connects the reference thermal equivalent circuit of the electric wire and models it as a device DW having terminals TW1, TW2, and TW3 for connecting the thermal equivalent circuit of the electric wire to the thermal equivalent circuits of other components of the series circuit SC. Figures 12 and 13 are diagrams showing examples of the thermal equivalent circuit of the electric wire modeled by the first modeling unit 112. Figure 12 shows the thermal equivalent circuit of the electric wire when the series circuit SC is not housed in a circuit case CC, and Figure 13 shows the thermal equivalent circuit of the electric wire when the series circuit SC is housed in a circuit case CC.

[0049] 12 and 13, terminals TW1 and TW2 of device DW are terminals for connecting to devices that model other components of series circuit SC. In Figures 12 and 13, terminal TW3 of device DW is a terminal for connecting to voltage source VSE that models the thermal equivalent circuit of the outside air or device DCC that models the thermal equivalent circuit of circuit case CC.

[0050] At each node of the thermal equivalent circuit of the electric wire, the relation between the temperature of the node and the temperature of the node adjacent to the node can be determined by Kirchhoff's law.

[0051] (Modeling of Thermal Equivalent Circuit of Fuse) When the series circuit SC includes a fuse as an electronic component, the first modeling unit 112 models the thermal equivalent circuit of the fuse as a device DF having terminals for connection to the thermal equivalent circuits of the other components of the series circuit SC. Figures 14 and 15 are diagrams showing examples of the thermal equivalent circuit of the fuse modeled by the first modeling unit 112. Figure 14 shows the thermal equivalent circuit of the fuse when the series circuit SC is not housed in a circuit case CC, and Figure 15 shows the thermal equivalent circuit of the fuse when the series circuit SC is housed in a circuit case CC.

[0052] 14 and 15, the fuse has a fusion portion, terminal portions provided on both ends of the fusion portion, and a case (fuse case) that covers the fusion portion. In Figures 14 and 15, nodes NFT1 and NFT2 correspond to the terminal portions on both ends, NFF corresponds to the fusion portion, and NFC corresponds to the fuse case.

[0053] 14 and 15, the current source CSFF models the Joule heat generated in the molten portion, and the current source CSFT models the Joule heat generated in each of the terminal portions at both ends.

[0054] 14 and 15, the thermal resistance RFT is the thermal resistance in the heat transfer in the longitudinal direction of the terminal (the direction in which the fusion zone extends), and the thermal resistance RFF is the thermal resistance in the heat transfer in the longitudinal direction of the fusion zone. The thermal resistances RFT and RFF are calculated using the following formulas. Here, LFT is the longitudinal length of the terminal portion, λFT is the thermal conductivity of the terminal portion, SFT is the cross-sectional area of ​​the terminal portion when the terminal portion is cut along a plane perpendicular to the longitudinal direction, LFF is the longitudinal length of the fusion portion, λFF is the thermal conductivity of the fusion portion, and SFF is the cross-sectional area of ​​the fusion portion when the fusion portion is cut along a plane perpendicular to the longitudinal direction. In Figures 14 and 15, the node NFT (NFF) corresponds to one end of the terminal portion (fusion portion), but the node NFT (NFF) may also correspond to the longitudinal center portion of the terminal portion (fusion portion). In this case, the thermal resistance of the heat transfer in the longitudinal direction of the terminal portion (fusion portion) is arranged on both sides of the node NFT (NFF) with a thermal resistance value of RFT / 2 (RFF / 2).

[0055] 14 and 15, the thermal resistance RFFC is the thermal resistance in the heat transfer from the fusion zone to the fuse case, and is calculated by thermal fluid analysis.

[0056] 14 and 15, the thermal resistance RFC is the thermal resistance in the heat transfer from the inside to the outside of the fuse case. The thermal resistance RFC is calculated, for example, by the following formula: Here, LFC is the longitudinal length of the fuse case, λFC is the thermal conductivity of the fuse case, and SFC is the cross-sectional area of ​​the fuse case when the fuse case is cut along a plane perpendicular to the longitudinal direction.

[0057] 14, thermal resistance RFCE is the thermal resistance in heat transfer from the fuse case to the external air (air outside the fuse case), and thermal resistance RFTE is the thermal resistance in heat transfer from the terminal portion to the external air. Thermal resistance RFCE is the combined thermal resistance of the convection heat transfer resistance RFCE1 from the fuse case to the external air and the radiation heat transfer resistance RFCE2 from the fuse case to the external air, and thermal resistance RFTE is the combined thermal resistance of the convection heat transfer resistance RFTE1 from the terminal portion to the external air and the radiation heat transfer resistance RFTE2 from the terminal portion to the external air. Thermal resistances RFCE and RFTE are calculated as follows: The convective heat transfer resistances RFCE1 and RFTE1 and the radiative heat transfer resistances RFCE2 and RFTE2 are calculated by thermal fluid analysis.

[0058] 15 , thermal resistance RFCC is the thermal resistance in heat transfer from the fuse case to the circuit case CC via the internal air (the air inside the circuit case CC), and thermal resistance RFTC is the thermal resistance in heat transfer from the terminal portion to the circuit case CC via the internal air. Thermal resistance RFCC is the combined thermal resistance of the convection heat transfer resistance RFCC1 from the fuse case to the circuit case CC via the internal air and the radiation heat transfer resistance RFCC2 from the fuse case to the case via the internal air. Thermal resistance RFTC is the combined thermal resistance of the convection heat transfer resistance RFTC1 from the terminal portion to the circuit case CC via the internal air and the radiation heat transfer resistance RFTC2 from the terminal portion to the circuit case CC via the internal air. Thermal resistances RFCC and RFTC are calculated as follows: The convective heat transfer resistances RFCC1 and RFTC1 and the radiative heat transfer resistances RFCC2 and RFTC2 are calculated by thermal fluid analysis.

[0059] 14 and 15, terminals TF1 and TF2 of device DF are terminals for connecting to devices that model other components of series circuit SC. In Figures 14 and 15, terminal TF3 of device DF is a terminal for connecting to voltage source VSE that models the thermal equivalent circuit of the outside air or device DCC that models the thermal equivalent circuit of circuit case CC.

[0060] At each node of the thermal equivalent circuit of the fuse, the relational expression between the temperature of that node and the temperature of the node adjacent to that node can be found by Kirchhoff's law.

[0061] 14 and 15, the fusion zone is shown as a single node, but the fusion zone may be divided into multiple parts like a bus bar or an electric wire, and may be represented as multiple nodes NFF1, NFF2, ..., NFFn, as shown in Fig. 16. Fig. 16 shows a thermal equivalent circuit of a fuse when the fuse is not housed in a circuit case CC. In this case, thermal resistance RFF is the thermal resistance of heat transfer in the longitudinal direction of each of the divided fusion zones, LFF is the longitudinal length of each of the divided fusion zones, thermal resistance RFFC is the thermal resistance of heat transfer from each of the divided fusion zones to the fuse case, and current source CSFF models the Joule heat generated in each of the divided fusion zones.

[0062] (Modeling of Thermal Equivalent Circuit of Contactor) When the series circuit SC includes a contactor as an electronic component, the first modeling unit 112 models the thermal equivalent circuit of the contactor as a device DCC having terminals for connection to the thermal equivalent circuits of the other components of the series circuit SC. Figures 17 and 18 are diagrams showing examples of the thermal equivalent circuit of the contactor modeled by the first modeling unit 112. Figure 17 shows the thermal equivalent circuit of the contactor when the contactor is not housed in a circuit case CC, and Figure 18 shows the thermal equivalent circuit of the contactor when the contactor is housed in a circuit case CC.

[0063] 17 and 18 includes a contact, a coil, and a case (contactor case) that covers the contact and the coil. In Figures 14 and 15, node NCS corresponds to the contact, NCI corresponds to the coil, and NCC corresponds to the contactor case.

[0064] In FIGS. 17 and 18, the current source CSCS models the Joule heat generated at the contacts, and the current source CSCI models the Joule heat generated in the coil.

[0065] 17 and 18, the thermal resistance RCS is the thermal resistance in the heat transfer in the longitudinal direction of the contact (direction in which the contact extends), and the thermal resistance RCS is calculated by the following formula. Here, LCS is the length of the contact in the longitudinal direction, λCS is the thermal conductivity of the contact, and SCS is the cross-sectional area of ​​the contact when the contact is cut along a plane perpendicular to the longitudinal direction. In Figures 17 and 18, node NCS corresponds to one end of the contact, but node NCS may also correspond to the center portion of the contact in the longitudinal direction. In this case, the thermal resistance of the heat transfer in the longitudinal direction of the contact is arranged on both sides of node NCS with a thermal resistance value of RCS / 2.

[0066] 17 and 18, thermal resistance RSI is the thermal resistance in heat transfer from the contact to the coil, thermal resistance RSC is the thermal resistance in heat transfer from the contact to the contactor case, and thermal resistance RIC is the thermal resistance in heat transfer from the coil to the contactor case. The thermal resistances RSI, RSC, and RIC are calculated by thermal fluid analysis.

[0067] 17 and 18, the thermal resistance RCC is the thermal resistance in the heat transfer from the inside to the outside of the contactor case. The thermal resistance RCC is calculated, for example, by the following formula: Here, LCC is the longitudinal length of the contactor case, λCC is the thermal conductivity of the contactor case, and SCC is the cross-sectional area of ​​the contactor case when the contactor case is cut along a plane perpendicular to the longitudinal direction.

[0068] 17, the thermal resistance RCCE is the thermal resistance in heat transfer from the contactor case to the external air (air outside the contactor). The thermal resistance RCCE is the combined thermal resistance of the convection heat transfer resistance RCCE1 from the contactor case to the external air and the radiation heat transfer resistance RCCE2 from the contactor case to the external air, and is calculated as follows: The convection heat transfer resistance RCCE1 and the radiation heat transfer resistance RCCE2 are calculated by thermal fluid analysis.

[0069] 18, thermal resistance RCCC is the thermal resistance in heat transfer from the contactor case to the circuit case CC via the internal air (air inside the circuit case CC). Thermal resistance RCCC is the combined thermal resistance of convection heat transfer resistance RCCC1 from the contactor case to the circuit case CC via the internal air and radiation heat transfer resistance RCCC2 from the contactor case to the case via the internal air, and is calculated as follows: In addition, the convection heat transfer resistance RCCC1 and the radiation heat transfer resistance RCCC2 are calculated by thermal fluid analysis.

[0070] 17 and 18, terminals TC1 and TC2 of device DCC are terminals for connecting to devices that model other components of series circuit SC. In Figures 17 and 18, terminal TC3 of device DCC is a terminal for connecting to voltage source VSE that models the thermal equivalent circuit of outside air or device DCC that models the thermal equivalent circuit of circuit case CC.

[0071] At each node of the thermal equivalent circuit of the contactor, the relational expression between the temperature of that node and the temperature of the node adjacent to that node can be found by Kirchhoff's law.

[0072] <Second modeling unit 113> The second modeling unit 113 connects the thermal equivalent circuits modeled by the first modeling unit 112 to each other via terminals, and models a thermal equivalent circuit of the series circuit SC. Fig. 19 is a diagram showing an example of the thermal equivalent circuit of the series circuit SC in the example of the series circuit SC shown in Fig. 2. In Fig. 19, devices DW1 and DW2 model the electric wires W1 and W2, devices DB1, DB2, and DB3 model the bus bars B1, B2, and B3, device DF models the fuse F, and device DCC models the contactor C.

[0073] For each node in the thermal equivalent circuit of the series circuit SC modeled by the second modeling unit 113, the relationship between the temperature of that node and the temperature of the node adjacent to that node can be determined using Kirchhoff's law. In other words, the relationship between the temperature of each node and the temperature of the node adjacent to that node can be determined using Kirchhoff's law if the thermal resistance values ​​included in the thermal equivalent circuit of the series circuit SC, the heat flow values ​​provided by the current sources, and the temperature values ​​of the voltage sources are known. Therefore, the information acquisition processing unit 111 may acquire the thermal resistance values ​​included in the thermal equivalent circuit of each component, the heat flow values ​​provided by the current sources, and the temperature values ​​of the voltage sources as parameters for each component of the series circuit SC. Furthermore, the thermal resistance values ​​and the heat flow values ​​provided by the current sources included in the thermal equivalent circuit of each component can also be calculated using parameters such as the size (length and cross-sectional area) of the component, the value of the current flowing through the component, the resistance value of the component, and the thermal conductivity of the component. Therefore, the information acquisition processing unit 111 may acquire, as parameters for each of the components of the series circuit SC, the value of the thermal resistance included in the thermal equivalent circuit of the component, parameters used to calculate the value of the heat flow supplied by the current source (for example, the size of the component (for example, length or cross-sectional area), the value of the current flowing through the component, the resistance value of the component, and the thermal conductivity of the component).

[0074] The above description of this embodiment uses a steady-state thermal equivalent circuit. The temperature distribution calculation unit 114 can also calculate a temperature distribution in an unsteady state by considering the heat capacity of each node (i.e., the heat capacity of the bus bar per first length, the heat capacity of each element of the electric wire per second length, the heat capacity of each element of the fuse and contactor, and the heat capacity of the circuit case). When calculating the temperature distribution in an unsteady state, the information acquisition processing unit 111 calculates a relationship between the temperature of each node in the thermal equivalent circuit of the bus bar and the temperature of a node adjacent to that node, taking into account the heat capacity of each node. Therefore, when calculating the temperature distribution in an unsteady state, it is preferable that the information acquisition processing unit 111 further acquires the initial temperature of each node of the components of the series circuit SC (i.e., the initial temperature of the bus bar per first length, the initial temperature of each element of the electric wire per second length, the initial temperature of each element of the fuse and contactor, and the initial temperature of the circuit case) and the heat capacity of each node of the components of the series circuit SC.

[0075] <Cooling of Components of Series Circuit SC> The components of the series circuit SC may be cooled by a cooling unit (e.g., a water-cooling unit). If the series circuit SC includes a bus bar, it is preferable that at least a portion of the bus bar be cooled by the cooling unit. Figures 20 and 21 are diagrams showing examples of thermal equivalent circuits of bus bars modeled by the first modeling unit 112. Figure 20 shows the thermal equivalent circuit of a bus bar when the bus bar is not housed in a circuit case CC, and Figure 21 shows the thermal equivalent circuit of a bus bar when the bus bar is housed in a circuit case CC.

[0076] 20 and 21, the portion of the bus bar corresponding to the node NB3 is cooled by the cooling unit, and the portions of the bus bar corresponding to the nodes NB1, NB2, and NBn are not cooled by the cooling unit.

[0077] 20 and 21, the node NM corresponds to a cooling unit.

[0078] 20 and 21, the voltage source VSM models the temperature of the cooling unit, and the thermal resistance RBM is the thermal resistance in the heat transfer from the bus bar to the cooling unit. The thermal resistance RBM is calculated by thermal fluid analysis.

[0079] In Figure 20, thermal resistance RME is the thermal resistance in heat transfer from the cooling unit to the external air (air outside the cooling unit), and is the combined thermal resistance of the convection heat transfer resistance RME1 from the cooling unit to the external air and the radiation heat transfer resistance RME2 from the cooling unit to the external air, and is calculated as follows using the convection heat transfer resistance RME1 and the radiation heat transfer resistance RME2: The convection heat transfer resistance RME1 and the radiation heat transfer resistance RME2 are calculated by thermal fluid analysis.

[0080] In Figure 21, thermal resistance RMC is the thermal resistance in heat transfer from the cooling unit to the circuit case CC via the internal air (the air inside the circuit case CC), and is the combined thermal resistance of the convection heat transfer resistance RMC1 from the cooling unit to the circuit case CC via the internal air and the radiation heat transfer resistance RMC2 from the cooling unit to the circuit case CC via the internal air, and is calculated as follows using the convection heat transfer resistance RMC1 and the radiation heat transfer resistance RMC2: The convection heat transfer resistance RMC1 and the radiation heat transfer resistance RMC2 are calculated by thermal fluid analysis.

[0081] 20 and 21, the terminal TB4 of the device DB is a terminal for connecting to the cooling unit via the thermal resistor RBM.

[0082] When the series circuit SC includes multiple bus bars, it is preferable to cool these multiple bus bars using a single cooling unit. In the example shown in Fig. 2, if each of the bus bars B1, B2, and B3 is partially cooled by a single cooling unit, the thermal equivalent circuit of the series circuit SC will be as shown in Figs. 22 and 23, for example.

[0083] 22 and 23, thermal resistance RM is the thermal resistance in the direction of heat transfer in the direction in which the refrigerant flows in the cooling unit. Thermal resistance RM is calculated based on the flow rate and thermal conductivity of the refrigerant in the cooling unit, the size of the cooling unit (e.g., the size of the part through which the refrigerant flows), etc.

[0084] In Fig. 22, the voltage source VSM is connected to the bus bar B1, so the bus bars B1, B2, and B3 are cooled in the order of B1, B2, and B3. In Fig. 23, the voltage source VSM is connected to the bus bar B3, so the bus bars B1, B2, and B3 are cooled in the order of B3, B2, and B1.

[0085] The information acquisition processing unit 111 may acquire a cooling order, which is the order in which the components of the series circuit SC are cooled, and the second modeling unit 113 may model a thermal equivalent circuit of the series circuit SC based on the cooling order acquired by the information acquisition processing unit 111. For example, in the example shown in Fig. 2 , if the cooling order acquired by the information acquisition processing unit 111 is the order of bus bars B1, B2, and B3, the second modeling unit 113 models the thermal equivalent circuit of the series circuit SC as shown in Fig. 22 , and if the cooling order acquired by the information acquisition processing unit 111 is the order of bus bars B3, B2, and B1, the second modeling unit 113 models the thermal equivalent circuit of the series circuit SC as shown in Fig. 23 .

[0086] The present invention has been described above in terms of preferred embodiments thereof. While the present invention has been described herein with reference to specific examples, various modifications and variations can be made to these examples without departing from the spirit and scope of the present invention as set forth in the claims.

[0087] REFERENCE SIGNS LIST 100 Analysis device 110 Control unit 111 Information acquisition processing unit 112 First modeling unit 113 Second modeling unit 114 Temperature distribution calculation unit 115 Output processing unit 120 Input unit 130 Storage unit 140 Output unit

Claims

1. An information processing device for analyzing the temperature distribution of a series circuit including electronic components, comprising: a first modeling unit that models the thermal equivalent circuit of each of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of other components of the series circuit; and a second modeling unit that connects the thermal equivalent circuits modeled by the first modeling unit to each other via the terminals, and models the thermal equivalent circuit of the series circuit.

2. An information processing device as described in claim 1, wherein at least a portion of the series circuit is housed within a case, and the first modeling unit models the thermal equivalent circuit of each of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuit of the other components of the series circuit, and terminals for connecting to the thermal equivalent circuit of external air or the thermal equivalent circuit of the case, and models the thermal equivalent circuit of the case as a device having terminals for connecting to the thermal equivalent circuit of a component of the series circuit housed within the case, and a terminal for connecting to the thermal equivalent circuit of external air.

3. An information processing device as described in claim 1 or 2, wherein the series circuit includes a bus bar, and the first modeling unit divides the bus bar into a plurality of parts, models a reference thermal equivalent circuit of an electric wire corresponding to the thermal equivalent circuit of the divided bus bar, connects the reference thermal equivalent circuit of the bus bar, and models the thermal equivalent circuit of the bus bar.

4. The information processing device according to claim 3, wherein at least a portion of the bus bar is cooled by a cooling unit.

5. The information processing device according to claim 4, wherein the series circuit includes a plurality of bus bars, the cooling unit cools the plurality of bus bars, and the second modeling unit models a thermal equivalent circuit of the series circuit based on the order in which the cooling unit cools the plurality of bus bars.

6. An information processing device as described in claim 1 or 2, wherein the series circuit includes an electric wire, and the first modeling unit divides the electric wire into a plurality of parts, models a reference thermal equivalent circuit of the electric wire corresponding to the thermal equivalent circuit of the divided electric wire, connects the reference thermal equivalent circuit of the electric wire, and models the thermal equivalent circuit of the electric wire.

7. The information processing device according to claim 1 or 2, wherein the electronic components include a fuse.

8. The information processing device according to claim 1 or 2, wherein the electronic components include a contactor.

9. An information processing method executed by a computer for analyzing temperature distribution in a series circuit including electronic components, comprising: a first modeling step of modeling each thermal equivalent circuit of components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of other components of the series circuit; and a second modeling step of connecting the thermal equivalent circuits modeled by the first modeling step to each other via the terminals, and modeling the thermal equivalent circuit of the series circuit.

10. An information processing program for causing a computer to execute the information processing method according to claim 9.

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