A round tube bolt connection type fuse thermal simulation equivalent model

Abstract

The application provides a round pipe bolt connection type fuse thermal simulation equivalent model, which comprises an equivalent left connecting terminal, an equivalent narrow neck structure, an equivalent quartz sand powder, an equivalent shell and an equivalent right connecting terminal; the equivalent quartz sand powder is arranged in the equivalent shell; the equivalent narrow neck structure is arranged in the equivalent quartz sand powder; and the equivalent left connecting terminal and the equivalent right connecting terminal are arranged at two ends of the equivalent shell respectively and connected with two end faces of the equivalent quartz sand powder respectively. The application realizes the effect of improving the precision and accuracy of thermal effect temperature in the thermal simulation of the fuse.

Description

Technical Field

[0001] This application relates to the technical field of thermal simulation equivalent models for fuses, and in particular to a thermal simulation equivalent model for a circular tube bolt connection type fuse. Background Technology

[0002] A fuse is a short-circuit and overcurrent protection device widely used in power electronics, inverters, new energy vehicle batteries, ship propulsion systems, high-speed trains, aerospace, and other fields. The primary function of a fuse is to protect the safe operation of a circuit. When the current exceeds a specified value for a certain period, the fuse melts its fusible element due to the heat generated, thus breaking the circuit. In power distribution systems, control systems, and electrical equipment, fuses are among the most commonly used protective devices for short circuits and severe overcurrents. Fuses have an inverse time-delay characteristic; that is, when the overload current is small, the fusing time is long; when the overload current is large, the fusing time is short. Therefore, within a certain overload current range, when the current returns to normal, the fuse will not melt and can continue to be used. Fuses have various fusing characteristic curves to meet the needs of different types of protected objects. A fuse is connected in series in a circuit. When an overload or short-circuit fault occurs in the circuit or electrical equipment, the fuse element melts first, cutting off the power supply and protecting the line or electrical equipment.

[0003] Battery packs in new energy vehicles are common sites of fire. Therefore, during the design phase, the thermal effects of many sub-modules, including the battery pack disconnect unit (BDU), must be considered. Thanks to the rapid development of Computer-Aided Engineering (CAE), computer simulations can be used to perform coupled calculations of Joule heating, fluid dynamics, and solid dynamics during BDU design, enabling the assessment of the thermal effects of the designed BDU. A BDU module includes several main components such as relays, fuses, copper busbars, plastic housings, wiring harnesses, fasteners, and connectors. Among these, fuses are electrical components with relatively high internal resistance and significant thermal effects within the BDU. When using ICEPAK software for BDU thermal simulation, the fuse geometry needs to be simplified; however, this simplification also affects the thermal effect, primarily manifested in the difference between the simulated and experimental temperatures. Currently, there is no publicly available method for simplifying the geometric model of such fuses in BDU thermal simulations.

[0004] Furthermore, existing technologies treat fuses as two equivalent parts: the casing and the copper busbar. The narrow neck structure, which is the main source of heat and melting inside the fuse, and the copper terminals at both ends are simplified to a single copper busbar. This leads to the neglect of the fact that the fuse primarily generates heat through the narrow neck structure. This existing equivalent scheme inevitably has a significant impact on the terminal temperature. Treating the casing and quartz sand powder as a single cylindrical unit results in low simulation accuracy.

[0005] Therefore, the urgent technical problem to be solved is: how to provide a thermal simulation equivalent model of the round tube bolt connection fuse commonly used in the circuit breaking unit of new energy vehicle battery packs, so as to improve the accuracy and precision of the thermal effect temperature during thermal simulation. Summary of the Invention

[0006] The purpose of this application is to provide an equivalent model for thermal simulation of a circular tube bolt-connected fuse, thereby improving the accuracy and precision of the thermal effect temperature during fuse thermal simulation.

[0007] To achieve the above objectives, this application provides a thermal simulation equivalent model of a circular tube bolt-connected fuse. The equivalent model includes: an equivalent left connecting terminal, an equivalent narrow neck structure, an equivalent quartz sand powder, an equivalent outer shell, and an equivalent right connecting terminal. The equivalent quartz sand powder is disposed inside the equivalent outer shell. The equivalent narrow neck structure is embedded within the equivalent quartz sand powder. The equivalent left connecting terminal and the equivalent right connecting terminal are respectively disposed at both ends of the equivalent outer shell and are respectively connected to the two end faces of the equivalent quartz sand powder.

[0008] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein an equivalent thermally conductive thin shell is provided between the equivalent quartz sand powder and the equivalent outer shell.

[0009] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent outer shell is cylindrical.

[0010] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent quartz sand powder is cylindrical.

[0011] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent thermally conductive thin shell is cylindrical, the equivalent thermally conductive thin shell is sleeved on the outer periphery of the equivalent quartz sand powder, and is in close contact with the outer wall of the equivalent quartz sand powder.

[0012] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent narrow neck structure is a planar thermally conductive thin shell;

[0013] The planar thermally conductive thin shell is embedded in the center of the equivalent quartz sand powder.

[0014] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein one end of the planar thermally conductive thin shell is connected to the equivalent left connection terminal, and the other end is connected to the equivalent right connection terminal.

[0015] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent narrow neck structure is an equivalent planar thermally conductive thin shell with zero thickness.

[0016] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent thermally conductive thin shell is a thermally conductive thin shell with an equivalent thickness of 0.

[0017] The equivalent thermal simulation model of the circular tube bolt connection fuse described above, wherein the equivalent left connection terminal and the equivalent right connection terminal are perpendicular to the end side of the equivalent quartz sand powder and connected to both ends of the equivalent quartz sand powder.

[0018] The beneficial effects achieved by this application are as follows:

[0019] (1) The narrow neck portion of the fuse in this application is equivalent to a planar thermally conductive thin shell with zero thickness, and the quartz sand powder is equivalent to a cylinder, while the terminals at both ends and the outer shell are kept in their original shapes. A thermally conductive thin shell with a zero-thickness cylindrical curved surface is embedded between the quartz sand and the outer shell, which improves the accuracy and precision of the thermal effect temperature during the thermal simulation of the fuse.

[0020] (2) This application provides a thermal simulation equivalent model of a circular tube bolt connection fuse. This method simplifies the process, eliminating the need for meshing the narrow neck part during simulation, thus reducing the computational load. Furthermore, the thermal effect results are in good agreement with the experimental results. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 This is a schematic diagram of the thermal simulation equivalent model of a circular tube bolt connection fuse according to an embodiment of this application.

[0023] Figure 2 This is a schematic diagram illustrating a usage scenario of an equivalent thermal simulation model of a circular tube bolt-connected fuse according to an embodiment of this application.

[0024] Figure 3 This is a flowchart illustrating a simplified thermal simulation model of a circular tube bolt-connected fuse according to an embodiment of this application.

[0025] Figure 4 The temperature field cloud map is a simulation result of the thermal effect of the fuse in this application embodiment.

[0026] Figure 5 This is a temperature curve from a real test in an embodiment of this application.

[0027] Reference numerals: 1-Equivalent left connecting terminal; 2-Equivalent narrow neck structure; 3-Equivalent shell; 4-Equivalent thermally conductive thin shell; 5-Equivalent quartz sand powder; 6-Equivalent right connecting terminal; 7-First connecting end; 8-Second connecting end. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0029] This invention provides a thermal simulation equivalent model for the circular tube bolt-connected fuse commonly used in the battery pack circuit breaker (BDU) of new energy vehicles. The circular tube bolt-connected fuse used in the BDU of new energy vehicles mainly consists of a shell, internal heat-insulating quartz sand, two terminals, and an internal porous heat-generating resistance sheet (referred to as the neck). The internal heat-insulating quartz sand and the internal porous heat-generating resistance sheet are located inside the shell; the two terminals are located at both ends of the shell. The relatively complex neck section is the main heat-generating part; therefore, the equivalent model of the neck section is most critical to its impact on the thermal effect.

[0030] Example 1

[0031] like Figure 1 As shown, this application provides a thermal simulation equivalent model of a circular tube bolt-connected fuse. The equivalent model includes: an equivalent left connecting terminal 1, an equivalent narrow neck structure 2, an equivalent quartz sand powder 5, an equivalent outer shell 3, and an equivalent right connecting terminal 6. The equivalent left connecting terminal 1 and the equivalent right connecting terminal 6 are used as the two ends of the equivalent fuse; the equivalent narrow neck structure 2 is used for the narrow neck portion of the equivalent fuse; the equivalent outer shell 3 is used for the outer shell of the equivalent fuse; and the equivalent quartz sand powder 5 is used for the quartz sand in the equivalent fuse. The equivalent quartz sand powder 5 is disposed inside the equivalent outer shell 3, and the equivalent narrow neck structure 2 is built into the equivalent quartz sand powder 5; the equivalent left connecting terminal 1 and the equivalent right connecting terminal 6 are respectively disposed at both ends of the equivalent outer shell 3 and are respectively connected to the two end faces of the equivalent quartz sand powder 5. This invention establishes an equivalent thermal simulation model for a circular tube bolt-connected fuse, used for thermal effect simulation experiments of the fuse. This improves the accuracy and precision of the thermal effect temperature during fuse thermal simulation, thereby evaluating the thermal effect of the fuse. Based on the thermal effect of the fuse, its reliability can be judged. If the fuse is reliable, it can be used in a BDU (Battery Pack Disconnect Unit) to protect the electrical components therein. Otherwise, if an unreliable fuse is used in a BDU, it may easily lead to dangerous accidents.

[0032] As a specific embodiment of the present invention, the two ends of the fuse are equivalent to: an equivalent left connecting terminal 1 and an equivalent right connecting terminal 6. The equivalent left connecting terminal 1 and the equivalent right connecting terminal 6 maintain the original shape of the two ends of the fuse, that is, the left connecting terminal and the equivalent right connecting terminal 6 are the same as the original shape of the two ends of the fuse. This makes the terminals in the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention have a better equivalence effect with the terminals of the fuse. Therefore, when using the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention to simulate the fuse, the accuracy and precision of the thermal effect temperature during the thermal simulation of the fuse are improved.

[0033] As a specific embodiment of the present invention, the fuse housing is equivalent to an equivalent housing 3. The shape of the equivalent housing 3 maintains the original shape of the fuse housing, that is, the shape of the equivalent housing 3 is the same as the actual shape of the fuse housing. This makes the housing in the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention have a better equivalence effect with the fuse housing. Therefore, when using the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention to simulate the fuse, the accuracy and precision of the thermal effect temperature during the thermal simulation of the fuse are improved.

[0034] As a specific embodiment of the present invention, the quartz sand powder inside the fuse is equivalent to a cylindrical solid, that is, equivalent quartz sand powder 5. This makes the equivalent quartz sand powder 5 in the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention have a better equivalence effect with the quartz sand powder of the fuse. Therefore, when using the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention to simulate the fuse, the accuracy and precision of the thermal effect temperature during the thermal simulation of the fuse are improved.

[0035] like Figure 1 As shown, an equivalent thermally conductive thin shell 4 is provided between the equivalent quartz sand powder 5 and the equivalent outer shell 3. That is, a cylindrical curved thermally conductive thin shell is embedded between the quartz sand and the outer shell. To account for the actual temperature influence of the quartz sand powder (powdered quartz sand) in the fuse on the outer shell, an equivalent thermally conductive thin shell 4 is provided between the equivalent quartz sand powder 5 and the equivalent outer shell 3, thereby improving the accuracy and precision of the fuse's thermal effect temperature during thermal simulation.

[0036] As a preferred embodiment of the present invention, the equivalent outer shell 3 is cylindrical, which makes the equivalent outer shell 3 in the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention have a better equivalent effect with the fuse shell, thereby improving the accuracy and precision of the fuse thermal effect temperature during thermal simulation of the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention.

[0037] As a preferred embodiment of the present invention, the equivalent quartz sand powder 5 is cylindrical, which makes the equivalent quartz sand powder 5 in the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention have a better equivalent effect with the quartz sand powder of the fuse, thereby improving the accuracy and precision of the fuse thermal effect temperature during thermal simulation of the thermal simulation equivalent model of the circular tube bolt connection fuse of the present invention.

[0038] In a preferred embodiment of the present invention, the equivalent thermally conductive thin shell 4 is cylindrical and is fitted around the outer periphery of the equivalent quartz sand powder 5, and is closely connected to the outer wall of the equivalent quartz sand powder 5. This improves the accuracy and precision of the fuse thermal effect temperature during thermal simulation of the equivalent model of the circular tube bolt connection fuse of the present invention.

[0039] In a preferred embodiment of the present invention, the equivalent narrow neck structure 2 is a planar thermally conductive thin shell, which has a thermally conductive function and transfers heat to the equivalent quartz sand powder 5. The equivalent quartz sand powder 5 transfers heat to the equivalent thermally conductive thin shell 4, and the equivalent thermally conductive thin shell 4 transfers heat to the equivalent outer shell 3.

[0040] In a preferred embodiment of the present invention, a planar thermally conductive thin shell is embedded in the center of the equivalent quartz sand powder 5.

[0041] like Figure 1 As shown, one end of the equivalent narrow neck structure 2 is connected to the equivalent left connection terminal 1, and the other end is connected to the equivalent right connection terminal 6. Specifically, one end of the planar thermally conductive thin shell is connected to the equivalent left connection terminal 1, and the other end is connected to the equivalent right connection terminal 6.

[0042] In a preferred embodiment of the present invention, the equivalent narrow neck structure 2 is a planar thermally conductive thin shell with an equivalent thickness of 0. It is understood that the present invention simplifies the narrow neck portion into a thin sheet with a geometric thickness of 0.

[0043] As a preferred embodiment of the present invention, the equivalent thermally conductive shell 4 is a thermally conductive shell with an equivalent thickness of 0.

[0044] In a preferred embodiment of the present invention, the equivalent left connecting terminal 1 and the equivalent right connecting terminal 6 are perpendicular to the end side of the equivalent quartz sand powder 5 and are connected to both ends of the equivalent quartz sand powder 5.

[0045] like Figure 2The diagram illustrates the application scenario of the equivalent fuse in a BDU product. The equivalent fuse thermal simulation model is connected to other electrical components and is in a conductive state, generating Joule heat. This invention provides a thermal simulation equivalent model of a circular tube bolt-connected fuse connected to the circuit of the BDU requiring protection. The circuit of the BDU requiring protection includes a first connection terminal 7 and a second connection terminal 8, which are disconnected. The thermal simulation equivalent model of the circular tube bolt-connected fuse of this invention is connected between the first connection terminal 7 and the second connection terminal 8. Specifically, the equivalent left connection terminal 1 is connected to the first connection terminal 7; the equivalent right connection terminal 6 is connected to the second connection terminal 8, thereby connecting the thermal simulation equivalent model of the circular tube bolt-connected fuse of this invention to the circuit of the BDU requiring protection.

[0046] As a specific embodiment of the present invention, the BDU (Battery Pack Disconnect Unit) includes electrical components such as relays, current sensors, fuses, pre-charge resistors, and connectors. As another specific embodiment, the equivalent fuse thermal simulation model is electrically connected to the relay via a conductive medium. The types of other electrical components in the BDU connected to the equivalent fuse thermal simulation model are not limited here; they can be other types of electrical components besides relays.

[0047] As a specific embodiment of the present invention, a method for simulating the thermal effect of a fuse using a circular tube bolt connection type fuse thermal simulation equivalent model is as follows: The thermal simulation equivalent model of the circular tube bolt connection type fuse of the present invention is connected to the circuit of the electrical components in the BDU (Battery Pack Circuit Breaker); the temperatures of the equivalent left connection terminal 1 and / or the equivalent right connection terminal 6 are collected; the temperature of either the equivalent left connection terminal 1 or the equivalent right connection terminal 6 can be collected, or both temperatures can be collected; the temperature of the equivalent casing 3 is also collected. The collected temperatures of the equivalent left connection terminal 1 and / or the equivalent right connection terminal 6, and the temperature of the equivalent casing 3, are taken as the fuse thermal effect temperature. Based on the fuse thermal effect temperature, the safety and reliability of the fuse used in the BDU (Battery Pack Circuit Breaker) are determined. The purpose of this invention is to establish a thermal simulation equivalent model for a circular tube bolt-connected fuse. The focus of this invention is not on how to determine the safety and reliability of a fuse used in a BDU (Battery Pack Disconnect Unit) based on its thermal effect temperature. Therefore, this invention will not elaborate on how to determine the safety and reliability of a fuse used in a BDU based on its thermal effect temperature. Those skilled in the art can determine the safety and reliability of a fuse used in a BDU based on its thermal effect temperature using existing methods.

[0048] As a specific embodiment of the present invention, a thermal simulation equivalent model of a circular tube bolt-connected fuse is established using finite element analysis software. Finite element analysis software includes ABAQUS, ANSYS, and MSC. The present invention does not limit the finite element analysis software used to establish a thermal simulation equivalent model of a circular tube bolt-connected fuse; any software capable of establishing such a model and performing thermal effect simulation on the fuse is acceptable.

[0049] Example 2

[0050] like Figure 3 As shown, this application provides an equivalent simplification method for the thermal simulation model of a circular tube bolt-connected fuse. The method includes the following steps:

[0051] Step S1: Equivalently convert the two ends of the fuse into an equivalent left connection terminal and an equivalent right connection terminal, respectively.

[0052] Specifically, equivalent left and equivalent right connection terminals are established. These terminals are used for the two ends of the equivalent fuse, and their shapes are the same as the actual shapes of the two ends of the fuse.

[0053] Step S2: Equivalently convert the fuse housing to an equivalent housing.

[0054] Specifically, an equivalent enclosure is established between the equivalent left connection terminal and the equivalent right connection terminal. The equivalent enclosure is used as the enclosure of the equivalent fuse, and the shape of the equivalent enclosure is the same as the actual shape of the fuse enclosure.

[0055] As a specific embodiment of the present invention, the material of the equivalent shell is the same as the actual material of the fuse shell; the size of the equivalent shell is the same as the actual size of the fuse shell, so as to improve the accuracy of the thermal effect temperature during fuse thermal simulation.

[0056] Step S3: The quartz sand powder inside the fuse is replaced with an equivalent cylindrical quartz sand powder.

[0057] Specifically, an equivalent quartz sand powder is built inside the equivalent outer shell. The equivalent quartz sand powder is used as the internal quartz sand powder of the equivalent fuse. The equivalent quartz sand powder is cylindrical in shape.

[0058] Step S4: An equivalent thermally conductive thin shell is embedded between the equivalent quartz sand powder and the equivalent outer shell.

[0059] Specifically, an equivalent thermally conductive thin shell is established between the equivalent quartz sand powder and the equivalent outer shell. This equivalent thermally conductive thin shell is used to transfer heat from the equivalent quartz sand powder to the equivalent outer shell. The established equivalent thermally conductive thin shell is a cylindrical curved surface structure with zero thickness, and it is embedded between the equivalent quartz sand powder and the equivalent outer shell.

[0060] It needs to be explained that the so-called zero-thickness cylindrical curved surface structure is indeed a curved surface. This means that setting the thickness to zero in the software generates a surface. Since the outer shell contains quartz sand powder, which consists of many dispersed particles encased within it, the software cannot model this granular material. Therefore, the quartz sand powder is modeled as a solid cylinder for easier modeling (i.e., constructing a thermal simulation model). However, this inevitably affects the overall thermal conductivity, as the thermal conductivity of the powder particles and the solid quartz sand is inherently different. Therefore, it is necessary to correct this thermal conductivity (equivalent to the quartz sand powder). Thus, a zero-thickness cylindrical thermally conductive thin shell is added between the equivalent quartz sand powder and the equivalent outer shell. Temperature is measured experimentally, and the thermal conductivity of the thin shell is then corrected in reverse. After correction, the overall temperature is brought closer to the experimental results (Note: the thermal conductivity is determined after correction and does not need to be corrected every time).

[0061] Step S5: Embed an equivalent narrow neck structure in the equivalent quartz sand powder.

[0062] Specifically, an equivalent narrow neck structure is embedded in the center of the equivalent quartz sand powder. This equivalent narrow neck structure is the key equivalent part, used for the narrow neck portion of the equivalent fuse. The established equivalent narrow neck structure is a planar thermally conductive thin shell with zero thickness, embedded in the equivalent quartz sand powder.

[0063] It needs to be explained that the actual internal narrow neck structure of a fuse is a porous, thin sheet structure. However, this structure is complex to model, and due to its thinness, it cannot be meshed in the software for subsequent calculations. Therefore, an equivalent treatment is necessary. The thickness of the narrow neck structure is much smaller than the thickness of the terminals at both ends. If it were simplified to a thicker structure, it would inevitably affect the heat conduction of the narrow neck structure to both ends. Therefore, considering these two factors, it is equivalent to a zero-thickness structure. Setting the thickness of the plane generated in the software to zero thickness generates a thin shell with zero thickness. A thin shell with zero thickness does not require meshing in the software, saving a significant amount of computation and improving the computational efficiency of the thermal simulation model.

[0064] As a specific embodiment of the present invention, a thermal simulation model of the equivalent simplified circular tube bolt-connected fuse is subjected to thermal effect simulation to obtain the thermal effect temperatures of the equivalent casing 3, equivalent left connecting terminal 1, and equivalent right connecting terminal 6. The simulation temperature results of the equivalent casing 3, equivalent left connecting terminal 1, and equivalent right connecting terminal 6 obtained from the thermal effect simulation are compared with the casing temperature and terminal temperature of the fuse in the actual temperature rise experiment to calculate the error degree of the thermal effect temperature during the thermal simulation of the equivalent model of the circular tube bolt-connected fuse.

[0065] like Figure 4As shown (in the following text, the temperature values ​​in the figure are only represented to two decimal places and are not rounded), this is a temperature field cloud map of the simulation results of the thermal effect of the fuse. As a specific simulation result of this invention: the temperature of the equivalent casing 3 is 58.39℃, and the temperature of the equivalent left connection terminal 1 or the equivalent right connection terminal 6 is 52.90℃. To compare with the simulation results and obtain the actual test temperature, as a specific embodiment of this invention, a real temperature rise test is performed on an existing fuse, such as... Figure 5 The figure shows the temperature curves obtained from a real temperature rise test of an existing fuse. In the curve, the temperatures of the terminals (including the left and right terminals) and the casing gradually increase and then stabilize. The stabilized casing temperature is 56.08℃, and the stabilized terminal temperature is 50.90℃. This means that the monitored casing temperature of the fuse in the actual temperature rise test was 56.08℃, and the terminal temperature was 50.90℃. Comparing the actual test temperatures with the thermal effect simulation results, the errors between the simulated casing temperature and the actual experimental temperature are: (58.39-56.08) / 56.08 = 4.11%, and the errors between the simulated terminal temperature and the actual experimental temperature are: (52.90-50.90) / 50.90 = 3.92%. Therefore, the thermal effect results are in good agreement with the actual experimental results.

[0066] As a specific embodiment of the present invention, the technical solution of the present invention is compared with the prior art:

[0067] The existing technical solution treats the fuse as two equivalent parts: the casing and the copper busbar. It simplifies the narrow neck structure, which is the main source of heat and melting, and the copper terminals at both ends of the fuse into a single copper busbar. The casing and the quartz sand powder are treated as a single cylindrical unit. This leads to the neglect of the fact that the fuse primarily generates heat through the narrow neck structure. This approach inevitably has a significant impact on the terminal temperature. As a specific experimental result of the existing technology, the simulated casing temperature is 46.69℃, and the terminal temperature is 68.79℃. It can be seen that the error between the simulated terminal temperature and the actual experimental temperature is (68.79-50.90) / 50.90 = 35.14%. Treating the entire terminal and narrow neck structure as a single unit results in a higher terminal temperature, 17.89℃ higher than the actual experimental temperature. When using this model for thermal simulation of the entire BDU product, the high temperature of the terminals is conducted to connected electrical components, causing the temperatures of other electrical components to also be higher than expected.

[0068] This invention improves the equivalent model of the narrow-necked structure by considering the left and right terminals, the narrow-necked structure, the quartz sand powder, and the outer shell separately, each equivalent to a single structure. As a specific embodiment of this invention, the error between the simulated temperature result and the actual experimental temperature of the fuse terminal is 3.92%. This 3.92% error is significantly smaller than the 35.14% error in the prior art. This invention overcomes the problem of overestimating the terminal simulation temperature caused by treating the terminal and narrow-necked structure as a single unit in existing technologies. It improves the accuracy and precision of the thermal effect temperature during fuse thermal simulation.

[0069] The beneficial effects achieved by this application are as follows:

[0070] (1) The narrow neck portion of the fuse in this application is equivalent to a planar thermally conductive thin shell, the quartz sand powder is equivalent to a cylinder, and the two terminals and the outer shell are kept in their original shapes. A cylindrical curved thermally conductive thin shell is embedded between the quartz sand and the outer shell, which improves the accuracy and precision of the thermal effect temperature during the thermal simulation of the fuse.

[0071] (2) This application provides a thermal simulation equivalent model of a circular tube bolt connection fuse. This method simplifies the process, eliminating the need for meshing the narrow neck part during simulation, thus reducing the computational load. Furthermore, the thermal effect results are in good agreement with the experimental results.

[0072] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0073] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A round tube bolted fuse thermal simulation equivalent model, characterized in that, The equivalent model comprises: an equivalent left connecting terminal, an equivalent narrow-neck structure, an equivalent quartz sand powder, an equivalent shell, and an equivalent right connecting terminal; The equivalent quartz sand powder is arranged inside the equivalent shell; The equivalent narrow-neck structure is embedded in the equivalent quartz sand powder; The equivalent left connecting terminal and the equivalent right connecting terminal are respectively arranged at two ends of the equivalent shell and are respectively connected with two end surfaces of the equivalent quartz sand powder; The equivalent narrow-neck structure is equivalent to a planar heat-conducting thin shell with a thickness of 0, the planar heat-conducting thin shell is embedded in the center of the equivalent quartz sand powder, and one end of the planar heat-conducting thin shell is connected with the equivalent left connecting terminal and the other end is connected with the equivalent right connecting terminal.

2. The circular tube bolted fuse thermal simulation equivalent model according to claim 1, characterized in that, An equivalent heat-conducting thin shell is arranged between the equivalent quartz sand powder and the equivalent shell.

3. The round tube bolted circuit breaker thermal simulation equivalent model according to claim 1, characterized in that, The equivalent shell is in a cylindrical shape.

4. The round tube bolted circuit breaker thermal simulation equivalent model according to claim 3, characterized in that, The equivalent quartz sand powder is in a cylindrical shape.

5. The round tube bolted circuit breaker thermal simulation equivalent model of claim 2, wherein, The equivalent heat-conducting thin shell is in a cylindrical shape, the equivalent heat-conducting thin shell is sleeved on the outer circumferential side of the equivalent quartz sand powder, and is connected with the outer wall of the equivalent quartz sand powder in a fit manner.

6. The circular tube bolted circuit breaker thermal simulation equivalent model according to claim 2 or 5, characterized in that, The equivalent heat-conducting thin shell is equivalent to a heat-conducting thin shell with a thickness of 0.

7. The circular tube bolted circuit breaker thermal simulation equivalent model of claim 1, wherein, The equivalent left connecting terminal and the equivalent right connecting terminal are perpendicular to the end side of the equivalent quartz sand powder and are connected at the two end sides of the equivalent quartz sand powder.

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