Information processor, information processing method, and information processing program

Abstract

To analyze the temperature distribution of circuits containing electronic components.SOLUTION: Each thermal equivalent circuit for the components in a series circuit is modeled as a device with terminals that connect to the thermal equivalent circuits of the other components in the series circuit. The thermal equivalent circuits modeled in the first modeling step are connected to each other via the terminals to model the thermal equivalent circuits of the series circuit.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] In recent years, the electrification of vehicles has been progressing. For this reason, the calorific value of electronic components and wire harnesses mounted on vehicles has been increasing, and design based on thermal analysis has become necessary (for example, Non-Patent Document 1). For example, Patent Document 1 discloses a method for analyzing the temperature distribution of a wire harness.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

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

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

Means for Solving the Problems

[0007] To solve the above problems, an information processing apparatus according to an embodiment of the present invention is an information processing apparatus for analyzing the temperature distribution of a series circuit including electronic components, and includes a first modeling unit that models each of the thermal equivalent circuits of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of the 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 to model the thermal equivalent circuit of the series circuit.

[0008] An information processing method according to an 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 each of the thermal equivalent circuits of the components of the series circuit as a device having terminals for connecting to the thermal equivalent circuits of the other components of the series circuit, and a second modeling step of connecting the thermal equivalent circuits modeled in the first modeling step to each other via the terminals to model the thermal equivalent circuit of the series circuit.

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

Advantages of the Invention

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

Brief Description of the Drawings

[0011]

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DETAILED DESCRIPTION OF THE INVENTION

[0012] <Analyzer 100> FIG. 1 is a diagram showing an analyzer 100 according to an embodiment of the present invention. The analyzer 100 includes 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 such as a computer. The input unit 120 is an input device that receives input of information such as a keyboard, a touch panel, a camera, and a microphone. The storage unit 130 is a storage device that stores information such as a hard disk drive, a solid state drive, and a memory. The output unit 140 is an output device that outputs information, and is, for example, a display device that displays information such as a display, a printing device that outputs printed information such as a printer, and 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 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 order of bus bar B1, fuse F, bus bar B2, contactor C, bus bar B3, and electric wire W2. Also, in the example shown in FIG. 2, among the series circuit SC, the bus bars B1 to B3, the fuse F, and the contactor C are housed in a case (circuit case CC). The circuit case CC is, for example, a junction box.

[0015] FIG. 3 is a diagram showing the control unit 110. The control unit 110 includes an input 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. Also, when information about the series circuit SC is stored in the storage unit 130, the information acquisition processing unit 111 acquires information about the series circuit SC from the storage unit 130. The information about the series circuit SC includes the connection relationship of the components of the series circuit SC, the relationship between the series circuit SC and the circuit case CC, and the parameters of each of the components.

[0017] When analyzing the temperature distribution of the series circuit SC shown in FIG. 2, the information acquisition processing unit 111 acquires information indicating that, as the connection relationship of the components, the electric wires W1, W2, bus bars B1 to B3, fuse F, and contactor C are connected in series in the order of bus bar B1, fuse F, bus bar B2, contactor C, bus bar B3, and electric wire W2. Further, as the relationship between the series SC and the circuit case CC, the information acquisition processing unit 111 acquires information indicating that among the series circuit SC, the electric wires W1 and W2 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. Then, the information acquisition processing unit 111 acquires the parameters of each of the electric wires W1, W2, bus bars B1 to B3, fuse F, and contactor C as the parameters of each component.

[0018] Based on the information regarding the series circuit SC acquired by the information acquisition processing unit 111, the first modeling unit 112 models each thermal equivalent circuit of the components of the series circuit SC as a device having terminals for connecting to the thermal equivalent circuits of the other components of the series circuit SC. In particular, if at least a part of the series circuit SC is housed in the circuit case CC, the first modeling unit 112 models each thermal equivalent circuit of the components of the series circuit SC as a device having terminals for connecting to the thermal equivalent circuits of the other components of the series circuit SC and terminals for connecting to the thermal equivalent circuit of the external air or the thermal equivalent circuit of the case, and models the thermal equivalent circuit of the circuit case CC as a device having terminals for connecting to the thermal equivalent circuits of the components housed in the circuit case CC among the components of the series circuit and terminals for connecting 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 not housed in the circuit case CC as a device DW having terminals TW1 and TW2 for connecting to other components as shown in Figs. 12 and 19, and a terminal TW3 for connecting to the thermal equivalent circuit VSE of the outside air. The thermal equivalent circuits of the bus bars B1 to B3, the fuse F, and the contactor C housed in the circuit case CC are modeled as devices DB, DF, and DC having terminals TB1, TB2, TF1, TF2, TC1, TC2 for connecting to other components and terminals TB3, TF3, TC3 for connecting to the device DCC that models the thermal equivalent circuit of the circuit case CC, as shown in Figs. 9, 15, 18, and 19. The circuit case CC is modeled as a device DCC having a terminal TCC1 for connecting to the devices DB, DF, and DC that model the thermal equivalent circuits of the bus bars B1 to B3, the fuse F, and the contactor C, which are components housed in the circuit case CC, and a terminal TCC2 for connecting to the thermal equivalent circuit VSE of the outside air, as shown in Figs. 9, 15, 18, and 19.

[0020] Based on the information regarding the series circuit SC acquired by the information acquisition processing unit 111, the second modeling unit 113 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.

[0021] When analyzing the temperature distribution of the series circuit shown in Fig. 2, for example, the first modeling unit 112 connects the thermal equivalent circuits DW, DB, DF, DC, and DCC modeled by the first modeling unit 112 to each other via the terminals TW1 to 3, TB1 to 3, TC1 to 3, and TCC1 to 2 to model 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. At this time, 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 obtains a relational expression between the temperature of the node and the temperature of the node adjacent to the node by Kirchhoff's law, solves these relational expressions simultaneously, and calculates the temperature of each node on the series circuit SC, thereby calculating the temperature distribution of the series circuit SC.

[0023] For the temperature distribution calculation unit 114, if the values of the thermal resistance included in the thermal equivalent circuit, the heat flow rate value supplied by the current source, and the temperature value of the voltage source are known, the relational expression between the temperature of each node and the temperature of the node adjacent to the node can be obtained by Kirchhoff's law. Therefore, the information acquisition processing unit 111 may acquire, as parameters of each component of the series circuit SC, the value of the thermal resistance included in the thermal equivalent circuit of the component, the heat flow rate value supplied by the current source, and the temperature of the voltage source (for example, the temperature of the external air). Also, the value of the thermal resistance included in the thermal equivalent circuit of the component and the heat flow rate value supplied by the current source can also be calculated based on 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 of each component of the series circuit SC, the parameters (for example, 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) used to calculate the value of the thermal resistance included in the thermal equivalent circuit of the component and the heat flow rate value supplied by the current source.

[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, for example, the output processing unit 115 outputs the temperature distribution of the series circuit SC by displaying the one-dimensional temperature distribution on a display device or printing the one-dimensional temperature distribution using a printing device.

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

[0026] FIG. 4 is a diagram showing an example of the processing operation in the control unit 110. The information acquisition processing unit 111 acquires information regarding the series circuit SC (step S401). The first modeling unit 112 models each of the heat equivalent circuits of the components of the series circuit SC as a device having terminals for connecting to the heat equivalent circuits of the other components of the series circuit SC based on the information regarding the series circuit SC (step S402). The second modeling unit 113 models the heat equivalent circuit of the series circuit SC by connecting the heat equivalent circuits modeled by the first modeling unit 112 to each other via terminals based on the information regarding the series circuit SC (step S403). The temperature distribution calculation unit 114 calculates the temperature distribution of the series circuit SC based on the heat 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] <The first modeling unit 112> When the series circuit SC includes a bus bar or an electric wire, or when the series circuit SC includes a fuse or a contact as an electronic component, the first modeling unit 112 models the heat equivalent circuits of the bus bar, the electric wire, the fuse, and the contact, which are the components of the series circuit SC, as devices having terminals for connecting to the heat equivalent circuits of the other components of the series circuit SC.

[0028] (Modeling of the heat 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 (for example, 1 cm), and models the reference heat equivalent circuit of the electric wire corresponding to the heat equivalent circuit of the bus bar for the divided first length.

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

[0030] In Figs. 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] In Figs. 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 external 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 by the value of the current flowing through the series circuit SC and the resistance value of the bus bar per unit first length. The temperature of the voltage source VSE is the temperature of the external air.

[0032] In Figs. 5 and 6, the thermal resistance RB is the thermal resistance in the heat transfer in the longitudinal direction (the direction in which the bus bar extends) of the bus bar. The thermal resistance RB is calculated, for example, by the following formula.

Equation

[0033] In FIG. 5, the thermal resistance RBE is the thermal resistance in the heat transfer from the bus bar to the external air (the air outside the bus bar). The thermal resistance RBE is the combined thermal resistance of the convective heat transfer resistance RBE1 from the bus bar to the external air and the radiative heat transfer resistance RBE2 from the bus bar to the external air. The convective heat transfer resistance RBE1 and the radiative heat transfer resistance RBE2 are calculated as follows.

Equation

Equation

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

Equation

[0035] In FIG. 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 equation.

Equation

[0036] In FIG. 6, the thermal resistance RCE is the thermal resistance in the heat transfer from the circuit case CC to the external air (the air outside the circuit case CC). The thermal resistance RCE is the combined thermal resistance of the convective heat transfer resistance RCE1 from the circuit case CC to the external air and the radiative heat transfer resistance RCE2 from the electric wire to the external air. The convective heat transfer resistance RCE1 and the radiative heat transfer resistance RCE2 are calculated as follows.

Equation

[0037] After the reference thermal equivalent circuit of the bus bar is modeled as described above, the first modeling unit 112 models the reference 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 and connecting the thermal equivalent circuit of the bus bar to the thermal equivalent circuits of the other components of the series circuit SC. FIGS. 8 and 9 are diagrams showing examples of the thermal equivalent circuit of the bus bar modeled by the first modeling unit 112. FIG. 8 shows the thermal equivalent circuit of the bus bar when the series circuit SC is not housed in the circuit case CC, and FIG. 9 shows the thermal equivalent circuit of the bus bar when the series circuit SC is housed in the circuit case CC. When the series circuit SC is housed in the 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] In FIGS. 8 and 9, the terminals TB1 and TB2 of the device DB are terminals for connecting to a device that models other components of the series circuit SC. In FIGS. 8 and 9, the terminal TB3 of the device DB is a terminal for connecting to a voltage source VSE that models the thermal equivalent circuit of the external air or a device DCC that models the thermal equivalent circuit of the case. In FIG. 8, the terminal TCC1 of the device DCC is a terminal for connecting to a device that models a component housed in the circuit case CC among the components of the series circuit SC, and the terminal TCC2 of the device DB is a terminal for connecting to a voltage source VSE that models the thermal equivalent circuit of the external air.

[0039] In FIGS. 8 and 9, in the steady state, among the heat fluxes flowing into the node NB2, that is, the heat flux QB flowing from the current source CSB into the node NB2 (that is, the Joule heat generated in the bus bar for the first length), the heat flux QNB22 flowing from the node NB1 into the node NB2 through the thermal resistance RB, the heat flux QNB23 flowing from the node NB3 into the node NB2 through the thermal resistance RB, and the heat flux QNB24 flowing from the voltage source VSE into the node NB2 through the thermal resistance RBE or from the node NC into the node NB2 through the thermal resistance RBC, Kirchhoff's law holds as follows.

Equation

Equation

Equation

[0040] (Modeling of Thermal Equivalent Circuit of Electric Wire) When the series circuit SC includes an electric wire, the first modeling unit 112 first divides the electric wire into a second length (for example, 1 cm), and models a reference thermal equivalent circuit of the electric wire corresponding to the thermal equivalent circuit of the bus bar for the divided second length.

[0041] FIGS. 10 and 11 are diagrams showing examples of the reference thermal equivalent circuit of the electric wire modeled by the first modeling unit 112. FIG. 10 shows the reference thermal equivalent circuit of the bus bar when the electric wire is not housed in the circuit case CC, and FIG. 11 shows the reference thermal equivalent circuit of the bus bar when the electric wire is housed in the circuit case CC.

[0042] The electric wire in the examples shown in FIGS. 10 and 11 has a conductor and an exterior material (for example, an insulator) arranged so as to cover the conductor around the conductor. In FIGS. 10 and 11, the node NWC corresponds to the conductor of the electric wire, and the node NWI corresponds to the exterior material of the conductor.

[0043] In FIGS. 10 and 11, the current source CSW models the heat source of the conductor of the electric wire.

[0044] In FIGS. 10 and 11, the thermal resistance RWC is the thermal resistance in the longitudinal direction (the direction in which the conductor extends) of the conductor of the electric wire, and the thermal resistance RWI is the thermal resistance in the longitudinal direction of the exterior material of the electric wire. The thermal resistances RWC and RWI are calculated, for example, by the following equations.

Equation

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

[0046] In FIG. 10, the thermal resistance RWIE is the thermal resistance in the heat transfer from the outer covering material of the electric wire to the external air (the air outside the electric wire). The thermal resistance RWIE is the combined thermal resistance of the convective heat transfer resistance RWIE1 from the outer covering material of the electric wire to the external air and the radiative heat transfer resistance RWIE2 from the outer covering material of the electric wire to the external air, and the convective heat transfer resistance RWIE1 and the radiative heat transfer resistance RWIE2 are calculated as follows.

Equation

[0047] In FIG. 11, the thermal resistance RWIC is the thermal resistance in the heat transfer from the outer covering material of the electric wire to the circuit case CC through the internal air (the air inside the circuit case CC). The thermal resistance RWIC is the combined thermal resistance of the convective heat transfer resistance RWIC1 from the outer covering material of the electric wire to the circuit case CC through the internal air and the radiative heat transfer resistance RWIC2 from the outer covering material of the electric wire to the circuit case CC through the internal air, and the convective heat transfer resistance RWIC1 and the radiative heat transfer resistance RWIC2 are calculated as follows.

Equation

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

[0049] In FIGS. 12 and 13, the terminals TW1 and TW2 of the device DW are terminals for connecting to a device that models the other components of the series circuit SC. In FIGS. 10 and 11, the terminal TW3 of the device DW is a terminal for connecting to a voltage source VSE that models the thermal equivalent circuit of the external air or a device DCC that models the thermal equivalent circuit of the circuit case CC.

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

[0051] (Modeling of the Thermal Equivalent Circuit of the 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 connecting the thermal equivalent circuit of the fuse to the thermal equivalent circuits of the other components of the series circuit SC. FIGS. 14 and 15 are diagrams showing examples of the thermal equivalent circuit of the fuse modeled by the first modeling unit 112. FIG. 14 shows the thermal equivalent circuit of the fuse when the series circuit SC is not housed in the circuit case CC, and FIG. 15 shows the thermal equivalent circuit of the fuse when the series circuit SC is housed in the circuit case CC.

[0052] In the examples shown in FIGS. 14 and 15, the fuse has a melting part, terminal parts provided at both ends of the melting part, and a case (fuse case) covering the melting part. In FIGS. 14 and 15, nodes NFT1 and NFT2 correspond to the terminal parts at both ends, NFF corresponds to the fuse, and NFC corresponds to the fuse case.

[0053] In FIGS. 14 and 15, current source CSFF models the Joule heat generated in the melting part, and current source CSFT models the Joule heat generated in each of the terminal parts at both ends.

[0054] In FIGS. 14 and 15, thermal resistance RFT is the thermal resistance in heat transfer in the longitudinal direction of the terminal part (the direction in which the melting part extends), and thermal resistance RFF is the thermal resistance in heat transfer in the longitudinal direction of the melting part. Thermal resistances RFT and RFF are calculated by the following formula.

Equation

[0055] In FIGS. 14 and 15, thermal resistance RFFC is the thermal resistance in heat transfer from the melting part to the fuse case. Thermal resistance RFFC is calculated by thermal fluid analysis.

[0056] In FIGS. 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. [Equation] Here, LFC is the 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.

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

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

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

[0060] Also, at each node of the thermal equivalent circuit of the fuse, the relational expression between the temperature of the node and the temperature of the nodes adjacent to the node can be obtained by Kirchhoff's law.

[0061] In FIGS. 14 and 15, the melting part is regarded as one node, but the melting part may be divided into a plurality as in the case of a bus bar or an electric wire, and may be regarded as a plurality of nodes NFF1, NFF2, ···, NFFn as shown in FIG. 16. FIG. 16 shows the thermal equivalent circuit of the fuse when the fuse is not housed in the circuit case CC. At this time, the thermal resistance RFF is the thermal resistance in the longitudinal heat transfer of each of the divided melting parts, LFF is the longitudinal length of each of the divided melting parts, the thermal resistance RFFC is the thermal resistance in the heat transfer from each of the divided melting parts to the fuse case, and the current source CSFF models the Joule heat generated in each of the divided melting parts.

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

[0063] The contacts in the examples shown in FIGS. 17 and 18 have a contact point, a coil, and a case (contact case) covering the contact point and the coil. In FIGS. 14 and 15, node NCS corresponds to the contact point, NCI corresponds to the coil, and NCC corresponds to the contact case.

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

[0065] In FIGS. 17 and 18, the thermal resistance RCS is the thermal resistance in the heat transfer in the longitudinal direction of the contact point (the direction in which the contact point extends), and the thermal resistance RCS is calculated by the following formula.

Equation

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

[0067] In FIGS. 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.

Equation

[0068] In FIG. 17, the thermal resistance RCCE is the thermal resistance in the heat transfer from the contactor case to the external air (the air outside the contactor). The thermal resistance RCCE is the combined thermal resistance of the convective heat transfer resistance RCCE1 from the contactor case to the external air and the radiative heat transfer resistance RCCE2 from the contactor case to the external air, and is calculated as follows.

Equation

[0069] In FIG. 18, the thermal resistance RCCC is the thermal resistance in the heat transfer from the contactor case to the circuit case CC through the internal air (the air inside the circuit case CC). The thermal resistance RCCC is the combined thermal resistance of the convective heat transfer resistance RCCC1 from the contactor case to the circuit case CC through the internal air and the radiative heat transfer resistance RCCC2 from the contactor case to the case through the internal air, and is calculated as follows.

Equation

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

[0071] Also, at each node of the thermal equivalent circuit of the contactor, the relational expression between the temperature of the node and the temperature of the node adjacent to the node can be obtained 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 the 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 case of the example of the series circuit SC shown in FIG. 2. In FIG. 19, the devices DW1 and DW2 model the wires W1 and W2, the devices DB1, DB2, and DB3 model the bus bars B1, B2, and B3, the device DF models the fuse F, and the device DC models the contactor C.

[0073] Also, for each node of the thermal equivalent circuit of the series circuit SC modeled by the second modeling unit 113, the relational expression between the temperature of the node and the temperature of the node adjacent to the node can be obtained by Kirchhoff's law. That is, if the value of the thermal resistance included in the thermal equivalent circuit of the series circuit SC, the value of the heat flow rate supplied by the current source, and the value of the temperature of the voltage source are known, the relational expression between the temperature of each node and the temperature of the node can be obtained by Kirchhoff's law. Therefore, the information acquisition processing unit 111 may acquire, as parameters of each component of the series circuit SC, the value of the thermal resistance included in the thermal equivalent circuit of the component, the value of the heat flow rate supplied by the current source, and the value of the temperature of the voltage source. Further, the value of the thermal resistance included in the thermal equivalent circuit of the component and the value of the heat flow rate supplied by the current source can also be calculated by 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 of each component of the series circuit SC, the parameters (for example, the size (for example, length and cross-sectional area) of the component, the value of the current flowing through the component, the resistance value of the component, the thermal conductivity of the component) used to calculate the value of the thermal resistance included in the thermal equivalent circuit of the component and the value of the heat flow rate supplied by the current source.

[0074] In the above description, the present embodiment has been described using a steady-state thermal equivalent circuit. The temperature distribution calculation unit 114 can also calculate the temperature distribution in the non-steady state by considering the heat capacity of each node (that is, the heat capacity of the bus bar per unit length of the first length, the heat capacity of each element of the wire per unit length of the second length, the heat capacity of each element of the fuse and the contactor, and the heat capacity of the circuit case). When calculating the temperature distribution in the non-steady state, after considering the heat capacity of each node, at each node of the thermal equivalent circuit of the bus bar, the relational expression between the temperature of the node and the temperature of the node adjacent to the node is obtained by Kirchhoff's law. Therefore, when calculating the temperature distribution in the non-steady 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 (that is, the initial temperature of the bus bar per unit length of the first length, the initial temperature of each element of the wire per unit length of the second length, the initial temperature of each element of the fuse and the 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 (for example, a water cooling unit). When the series circuit SC includes a bus bar, at least a part of the bus bar may be cooled by the cooling unit. FIGS. 20 and 21 are diagrams showing examples of the thermal equivalent circuit of the bus bar modeled by the first modeling unit 112. FIG. 20 shows the thermal equivalent circuit of the bus bar when the bus bar is not housed in the circuit case CC, and FIG. 21 shows the thermal equivalent circuit of the bus bar when the bus bar is housed in the circuit case CC.

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

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

[0078] In FIGS. 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 FIG. 20, the thermal resistance RME is the thermal resistance in the heat transfer from the cooling unit to the external air (the air outside the bus bar). The thermal resistance RME is the combined thermal resistance of the convective heat transfer resistance RME1 from the cooling unit to the external air and the radiative heat transfer resistance RME2 from the cooling unit to the external air, and the convective heat transfer resistance RME1 and the radiative heat transfer resistance RME2 are calculated as follows.

Equation

[0080] In FIG. 21, the thermal resistance RMC is the thermal resistance in the heat transfer from the cooling unit to the circuit case CC through the internal air (the air inside the circuit case CC). The thermal resistance RMC is the combined thermal resistance of the convective heat transfer resistance RMC1 from the cooling unit to the circuit case CC through the internal air and the radiative heat transfer resistance RMC2 from the cooling unit to the circuit case CC through the internal air, and the convective heat transfer resistance RMC1 and the radiative heat transfer resistance RMC2 are calculated as follows.

Equation

[0081] In FIGS. 20 and 21, the terminal TC4 of the device DB is a terminal for connecting to the cooling unit via the thermal resistance RBM.

[0082] When the series circuit SC includes a plurality of busbars, it is preferable to cool these plurality of busbars by one cooling unit. In the example shown in FIG. 2, when a part of each of the busbars B1, B2, and B3 is cooled by one cooling unit, the thermal equivalent circuit of the series circuit SC is, for example, as shown in FIGS. 22 and 23.

[0083] In FIGS. 22 and 23, the thermal resistance RM is the thermal resistance in the heat transfer in the direction in which the refrigerant of the cooling unit flows. The thermal resistance RM is calculated based on the flow rate of the refrigerant of the cooling unit, the thermal conductivity, the size of the cooling unit (for example, the size of the portion where the refrigerant flows), and the like.

[0084] In FIG. 22, since the voltage source VSM is connected to the busbar B1, the busbars B1, B2, and B3 are cooled in the order of busbars B1, B2, and B3. In FIG. 23, since the voltage source VSM is connected to the busbar B3, the busbars B1, B2, and B3 are cooled in the order of busbars B3, B2, and B1.

[0085] The information acquisition processing unit 111 acquires the cooling order, which is the order in which the components of the series circuit SC are cooled, and the second modeling unit 123 models the 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 case of the example shown in FIG. 2, if the cooling order acquired by the information acquisition processing unit 111 is in the order of busbars B1, B2, and B3, the second modeling unit 123 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 in the order of busbars B3, B2, and B1, the second modeling unit 123 models the thermal equivalent circuit of the series circuit SC as shown in FIG. 23.

[0086] The present invention has been described above according to the preferred embodiments of the present invention. Here, the present invention has been described by showing specific specific examples, but various modifications and changes can be made to these specific examples without departing from the spirit and scope of the present invention described in the claims.

Explanation of Reference Numerals

[0087] 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 apparatus for analyzing the temperature distribution of a series circuit including electronic components, a first modeling unit that models each thermal equivalent circuit of the components of the series circuit as a device having terminals for connecting the thermal equivalent circuit of each component to the thermal equivalent circuits of other components of the series circuit; a second modeling unit that connects the thermal equivalent circuits modeled by the first modeling unit to each other via the terminals to model the thermal equivalent circuit of the series circuit.

2. At least a part of the series circuit is housed in a case, and the first modeling unit models each thermal equivalent circuit of the components of the series circuit as a device having terminals for connecting the thermal equivalent circuit of each component to the thermal equivalent circuits of 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 the thermal equivalent circuit of the case to the thermal equivalent circuits of the components housed in the case among the components of the series circuit and terminals for connecting to the thermal equivalent circuit of external air. The information processing apparatus according to claim 1.

3. 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 a wire corresponding to the thermal equivalent circuit of the divided bus bar, connects the reference thermal equivalent circuits of the bus bar, and models the thermal equivalent circuit of the bus bar. The information processing apparatus according to claim 1 or 2.

4. At least a part of the bus bar is cooled by a cooling unit. The information processing apparatus according to claim 3.

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

6. The series circuit includes electric wires, 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 circuits of the electric wire, and models the thermal equivalent circuit of the electric wire, the information processing apparatus according to claim 1 or 2.

7. The electronic component includes a fuse, the information processing apparatus according to claim 1 or 2.

8. The electronic component includes a contactor, the information processing apparatus according to claim 1 or 2.

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

10. An information processing program that causes a computer to execute the information processing method according to claim 9.

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