System loop matching design method and device, computer equipment and storage medium

Abstract

The invention belongs to the technical field of electrical system loops, and relates to a system loop matching design method and device, computer equipment and a storage medium, and the method comprises the steps: obtaining load parameters in a system loop; calculating a load current according to the load parameter; according to a load current, selecting a fuse, defining a temperature resistance grade, and selecting a cable diameter; according to the selected fuse, the defined temperature resistance grade and the selected cable diameter, performing overcurrent matching checking, judging whether the overcurrent matching checking is passed or not, and if yes, performing temperature rise checking; judging whether the temperature rise checking is passed or not, and if so, checking the fuming time; and judging whether the verification of the fuming time is passed or not, and if so, carrying out electrical performance test confirmation. Multiple aspects such as electrical element performance, environmental factors and frequency factors are comprehensively considered, and the accuracy and reliability of the high-voltage system in the design process are ensured; failure risks can be effectively avoided, the safety and stability of the system are improved, and powerful support is provided for electric development of automobiles.

Description

Technical Field

[0001] This invention relates to the field of electrical system circuit technology, and in particular to system circuit matching design methods, devices, computer equipment and storage media. Background Technology

[0002] With the increasing electrification of automobiles, the complexity and diversity of electrical functions are becoming more and more important, making the design of high-voltage system circuit matching particularly crucial. When circuit matching problems occur, vehicles may face serious fire risks, thereby threatening the safety of passengers and the vehicle itself.

[0003] Existing system circuit matching designs only consider normal operating conditions and ignore various factors such as circuit capacity under overload conditions, which can lead to a series of serious safety hazards. Summary of the Invention

[0004] The purpose of this invention is to provide a system loop matching design method, apparatus, computer equipment, and storage medium to address the problem that existing system loop matching designs only consider normal operating conditions and ignore various factors such as the loop's capacity under overload conditions, which can lead to a series of serious safety hazards.

[0005] To address the aforementioned technical problems, this invention provides a system loop matching design method, employing the following technical solution, including the following steps:

[0006] S1. Obtain the load parameters in the system loop;

[0007] S2. Calculate the load current based on the load parameters;

[0008] S3. Select a fuse, define the temperature rating, and select the cable diameter based on the load current.

[0009] S4. Based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, perform overcurrent matching verification to determine whether the overcurrent matching verification passes. If it does, then perform temperature rise verification.

[0010] S5. Determine whether the temperature rise check passes. If yes, proceed to the smoke generation time check; otherwise, proceed to step S3.

[0011] S6. Determine whether the smoke emission time verification is passed. If so, conduct electrical performance testing for confirmation.

[0012] Preferably, step S1, obtaining the load parameters in the system loop, specifically includes:

[0013] S11. Determine the load type;

[0014] S12. Confirm the circuit operating current;

[0015] S13. The measured and confirmed load type, operating current, locked-rotor current, and locked-rotor time parameters are incorporated into the ICD table to achieve load parameter management. Preferably, step S2, calculating the load current based on the load parameters, specifically includes:

[0016] S21. Calculate the ratio of rated power to nominal voltage to obtain the first ratio;

[0017] S22. Calculate the ratio of the actual voltage to the nominal voltage to obtain the second ratio;

[0018] S23. The product of the first ratio and the second ratio is the load current.

[0019] Preferably, step S3, selecting a fuse, defining the temperature rating, and selecting the cable diameter based on the load current, specifically includes:

[0020] S31. Based on the load current, select a fuse with a rated current greater than the load current;

[0021] S32. Select the temperature resistance rating of the conductor according to the characteristics of the working environment;

[0022] S33. Based on the assessment results of circuit temperature rise and conductor smoke risk, select the conductor diameter. Preferably, step S4, based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, performs an overcurrent matching check to determine whether the overcurrent matching check passes. If it does, the temperature rise check specifically includes:

[0023] S41. Determine the characteristics of the fuse;

[0024] S42. Analyze system overcurrent;

[0025] S43. Current matching judgment.

[0026] Preferably, step S5, determining whether the temperature rise verification passes, and if so, performing a smoke generation time verification; otherwise, proceeding to step S3, specifically includes:

[0027] S51. Determine the operating current of the circuit based on the design and operating conditions of the electrical system;

[0028] S52. Obtain the DC resistance and thermal resistance parameters of the conductor;

[0029] S53. Substitute the known operating current, DC resistance of the conductor, and thermal resistance parameters into the formula to perform calculations. Based on the calculation results, evaluate whether the temperature rise of the circuit meets the requirements.

[0030] Preferably, step S6, determining whether the smoke generation time verification passes, and if so, performing electrical performance testing for confirmation, specifically includes:

[0031] S61. Determine the conductor temperature when the wire emits smoke;

[0032] S62. Confirm the thermal constant of the conductor;

[0033] S63. Based on the known smoke temperature and thermal constant of the conductor, calculate the time required for the conductor to reach the smoke temperature.

[0034] To address the aforementioned technical problems, the present invention also provides a system loop matching design device, which employs the following technical solution, including:

[0035] The acquisition module is used to acquire load parameters in the system loop;

[0036] The calculation module is used to calculate the load current based on the load parameters;

[0037] The selection module is used to select a fuse, define the temperature rating, and select the cable diameter based on the load current.

[0038] The first verification module is used to perform overcurrent matching verification based on the selected fuse, the defined temperature resistance rating and the selected cable diameter, and to determine whether the overcurrent matching verification passes. If it does, the temperature rise verification is performed.

[0039] The second verification module is used to determine whether the temperature rise verification passes; if it does, the smoke generation time verification is performed.

[0040] The confirmation module is used to determine whether the smoke emission time verification has passed. If so, electrical performance testing is performed for confirmation.

[0041] To address the aforementioned technical problems, the present invention also provides a computer device that employs the technical solution described below, comprising a memory and a processor. The memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the steps of the system loop matching design method described above.

[0042] To address the aforementioned technical problems, the present invention also provides a computer-readable storage medium, which employs the technical solution described below. The computer-readable storage medium stores computer-readable instructions, which, when executed by a processor, implement the steps of the system loop matching design method described above.

[0043] Compared with existing technologies, the present invention has the following main advantages: It comprehensively considers multiple key factors, including different operating conditions, temperature, thermal conductivity of connecting devices, air cooling effect, and frequency, to more comprehensively evaluate the performance of the system loop. By deeply analyzing the impact of these factors on loop performance, the behavior of the loop under different operating conditions can be predicted more accurately, and corresponding optimization designs can be completed accordingly. It not only considers the system loop's withstand capability under normal operating conditions but also emphasizes that the loop must meet design requirements under overload conditions to ensure the safety and stability of the system under various operating conditions. Attached Figure Description

[0044] To more clearly illustrate the solutions in this invention, the accompanying drawings used in the description of the embodiments of this invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a flowchart of an embodiment of the system loop matching design method of the present invention;

[0046] Figure 2 This is a system architecture diagram for implementing the system loop matching design method of the present invention;

[0047] Figure 3 This is a schematic diagram of the temperature factor correction curve;

[0048] Figure 4 This is a schematic diagram of the thermal conductivity factor curve of the connecting device;

[0049] Figure 5 This is a schematic diagram of the air-cooled correction factor curve;

[0050] Figure 6 This is a schematic diagram of the frequency factor correction curve;

[0051] Figure 7 This is a schematic diagram of a high-voltage conductor structure;

[0052] Figure 8 This is a schematic diagram of the matching curve between the conductor and the fuse;

[0053] Figure 9 This is a schematic diagram showing the smoke generation time under conductor overload current;

[0054] Figure 10 This is a schematic diagram of a structure of an embodiment of the system loop matching design device of the present invention;

[0055] Figure 11 This is a schematic diagram of the structure of an embodiment of the computer device of the present invention. Detailed Implementation

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects and not to describe a particular order.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0059] It should be noted that the system loop matching design method provided in the embodiments of the present invention is generally executed by a server / terminal device, and correspondingly, the system loop matching design device is generally set in the server / terminal device.

[0060] It should be understood that the number of terminal devices, networks, and servers is merely illustrative. Depending on implementation needs, any number of terminal devices, networks, and servers can be used.

[0061] Example 1

[0062] Continue to refer Figure 1 The flowchart illustrates an embodiment of the system loop matching design method of the present invention. The system loop matching design method includes the following steps:

[0063] Step S1: Obtain the load parameters in the system loop.

[0064] In this embodiment, the load parameters in the system circuit include, but are not limited to, rated voltage, rated power, nominal voltage, rated current, actual voltage, thermal performance, etc.

[0065] Rated power (W) refers to the rated power of the load. Nominal voltage (V) refers to the open-circuit output voltage, that is, the voltage without any load connected, which is generally the rated voltage of the battery pack. Actual voltage (V) refers to the voltage actually applied to the electrical load, which is generally the actual operating voltage of the battery pack.

[0066] Figure 2 This is a system architecture diagram for implementing the system loop matching design method of this invention. (Example) Figure 2 As shown, the system architecture implementing the system loop matching design method of this invention includes a PDU power distribution controller, a power battery module electrically connected to the PDU power distribution controller, a DC charging port, an on-board charger, a PTC heater, an electric compressor, a motor controller, fuses, wires, and electrical equipment. The power distribution unit (PDU) is responsible for power distribution and management in the high-voltage system solution. It electrically connects high-voltage components through busbars and wiring harnesses, thereby ensuring the normal operation of the vehicle's high-voltage system. The main functions of the PDU include charge / discharge control, high-voltage component power-on control, circuit overload and short-circuit protection, high-voltage sampling, and low-voltage control. These functions work together to protect and monitor the operation of the high-voltage system, ensuring the vehicle operates safely and stably under various operating conditions. The fuse melts and cuts off the current when the current abnormally rises to a certain level and temperature, thus protecting the circuit's safe operation. The wires are the carriers of current transmission, responsible for effectively transmitting the electrical energy generated by the power source to various electrical devices, ensuring the normal operation of the entire circuit system. The electrical equipment is responsible for executing vehicle functions.

[0067] In this embodiment, step S1, obtaining the load parameters in the system loop, may further include the following steps:

[0068] S11. Determine the load type.

[0069] Identify the type of load in the circuit, such as whether it is a resistive, inductive, or capacitive load. Different types of loads have different effects on the performance of the circuit.

[0070] S12. Confirm the circuit operating current.

[0071] Use tools such as a power analyzer to measure the actual operating current, stall current, stall time, and other parameters in the circuit.

[0072] S13. Incorporate the measured and confirmed load type, operating current, locked rotor current, and locked rotor time parameters into the ICD table to achieve load parameter management. Step S2: Calculate the load current based on the load parameters.

[0073] In this embodiment, step S2, calculating the load current based on the load parameters, specifically includes the following steps:

[0074] Calculate the ratio of rated power to nominal voltage to obtain the first ratio;

[0075] Calculate the ratio of the actual voltage to the nominal voltage to obtain the second ratio;

[0076] The product of the first ratio and the second ratio is the load current.

[0077] Step S3: Select a fuse, define the temperature rating, and select the cable diameter based on the load current.

[0078] In this embodiment, step S3, selecting a fuse based on the load current, defining the temperature rating, and selecting the cable diameter may further include the following steps:

[0079] S31. Select a fuse with a rated current greater than the load current based on the load current.

[0080] Select a fuse with a rated current greater than the load current based on the load current to ensure that the fuse will not trip accidentally under normal operating conditions.

[0081] S32. Select the temperature resistance rating of the conductor according to the characteristics of the working environment.

[0082] The characteristics of the working environment include the cabin, cockpit, chassis, etc., which requires consideration of the wire material, insulation performance, and temperature stability during long-term operation.

[0083] S33. Select the conductor diameter based on the assessment results of circuit temperature rise and conductor smoke risk.

[0084] The selection of wire diameter should ensure that the wire will not overheat under normal operating conditions and can meet the load current requirements. For high current protection, the selected fuse should have the following performance characteristics:

[0085] It can meet the system protection requirements under normal operating conditions of electrical appliances; it can withstand instantaneous high current and high pulse during the operation of electrical appliances; it can meet the actual operating temperature requirements of the vehicle; and it meets the requirements of the vehicle's life cycle.

[0086] The rated current of a fuse is usually based on the ambient temperature. To meet the actual operating conditions of electric vehicles, the rated current needs to be adjusted. Factors typically considered include temperature, heat conduction, cooling, and operating frequency. The rated current If of the fuse is calculated as follows:

[0087] If ≥ In / (Kt × Ke × Kv × Kf).

[0088] Where In is the rated load current of the circuit where the fuse is located, Kt is the temperature correction factor, Ke is the thermal conductivity factor of the connecting device, Kv is the air cooling correction factor, and Kf is the frequency correction factor.

[0089] Figure 3 This is a schematic diagram of the temperature factor correction curve. For example... Figure 3 As shown, the temperature coefficient is an important characteristic of fuses, referring to the degree to which the melting point of a fuse changes with temperature. Generally speaking, the higher the temperature, the weaker the fuse's withstand capability.

[0090] Figure 4 This is a schematic diagram of the thermal conductivity factor curve of the connecting device. For example... Figure 4 As shown, the thermal conductivity factor is an important parameter describing the thermal conductivity of a material, determining the efficiency of heat transfer within the material per unit time. For fuses, a certain amount of heat is generated during operation. If the thermal conductivity factor is low, the efficiency of heat transfer within the fuse will decrease, leading to an increase in the internal temperature and potentially causing fuse damage.

[0091] Figure 5 This is a schematic diagram of the air-cooled correction factor curve. For example... Figure 5 As shown, when a fuse is in operation, it generates heat due to the flow of current. If the fuse is installed in a well-ventilated environment, external airflow can effectively carry away this heat, thus keeping the fuse temperature within a relatively low and safe range. In this case, the air-cooling factor is high, and the fuse has good durability.

[0092] Figure 6 This is a schematic diagram of the frequency factor correction curve. For example... Figure 6 As shown, the frequency factor reflects the frequency characteristics of a fuse during operation, including the number of current cycles it withstands. In environments with high operating frequencies, the fuse needs to withstand more current cycles. This causes the internal materials of the fuse to experience more thermal stress, accelerating the aging and damage of the fuse.

[0093] In practice, after the initial selection of the fuse is completed, the fuse itself is tested for life and overload to achieve the final design state.

[0094] When defining the temperature resistance rating of conductor insulation sheaths, it is considered that the thermal radiation effect on the insulation material mainly comes from the ambient temperature of the cable's operating environment and the temperature rise caused by the current flowing through the cable. Therefore, the current carrying capacity of the conductor is limited by the ambient temperature. When the conductor temperature exceeds the allowable value, the insulation material will age rapidly, thus failing to guarantee safe use within the design life. The conductor's durability performance must meet at least 3000 hours, and its short-term aging performance must meet at least 240 hours.

[0095] The temperature resistance ratings of high-voltage conductor insulation and sheathing materials are detailed in Table 1.

[0096] Table 1

[0097] Insulation materials Sheath material Temperature resistance level PTFE (polytetrafluoroethylene) PTFE (polytetrafluoroethylene) +260℃ FEP (Fluoropropyl propylene rubber) FEP (Fluoropropyl propylene rubber) +205℃ XL-ETFE (crosslinked ethylene-tetrafluoroethylene copolymer) XL-ETFE (crosslinked ethylene-tetrafluoroethylene copolymer) +200℃ Silicone Silicone +180℃ ETFE (ethylene-tetrafluoroethylene copolymer) ETFE (ethylene-tetrafluoroethylene copolymer) +155℃ Irradiated cross-linked polyethylene Irradiated cross-linked polyethylene +150℃ PET (Polyterephthalic Acid) PET (Polyterephthalic Acid) +130℃ XLPO (crosslinked polyolefin) XLPO (crosslinked polyolefin) +125℃ TPE PUR (Polyurethane) +120℃ PVC / HFFR (Polyvinyl Chloride) PVC / HFFR +105℃ XLPE (cross-linked polyethylene) XLPE +90℃ HDPE (High-density polyethylene) HDPE +80℃ LDPE (Low-density polyethylene) LDPE +70℃

[0098] Regarding the temperature resistance rating of materials, vehicles are divided into several temperature zones according to different operating temperatures. The operating ambient temperatures of common new energy vehicle models are shown in Table 2 below:

[0099] Table 2

[0100] New energy vehicle types Operating ambient temperature pure electric -40℃～60℃ PHEV -40℃～150℃

[0101] Figure 7 This is a schematic diagram of a high-voltage conductor structure, such as... Figure 7 As shown, the common high-voltage conductor structure, from the inside out, consists of: conductor, insulation layer, inner lining filling layer, shielding layer, and outer sheath layer.

[0102] In terms of the number of cores, conductors are divided into single-core conductors and multi-core conductors. The selection of conductors generally takes into account the space and cost of the conductor itself. Multi-core double-shielded conductors with a cross-sectional area of ​​6mm2 and below are mostly used (the shielding layer is required to be 360°, tinned copper braid, and the braiding density should be ≥85%), while single-core double-shielded conductors are mostly used for conductors with a cross-sectional area of ​​6mm2 and above.

[0103] The current-carrying capacity of a conductor is calculated by considering that when current flows through the conductor, the conductor will generate heat, causing the conductor temperature to rise. Since the ambient temperature is relatively low, the conductor temperature will remain constant when the rate of temperature rise is roughly the same as the rate of heat dissipation from the conductor to the surrounding environment. At this point, the conductor temperature minus the ambient temperature is the temperature rise that the conductor can withstand.

[0104] According to Joule's law, the heat generated in a conductor when an electric current flows is: Q = I 2 rt, where Q represents heat in joules (J), I represents current in amperes (A), r represents resistance in ohms (Ω), and t represents time in seconds (s).

[0105] Some of the generated heat is stored within the conductor and insulation material, while the remainder is dissipated outwards through conduction, gradually transferring to the surface of the conductor's outer sheath. Due to thermal resistance between the conductor and insulation, between insulation and sheath, and between the sheath and the surrounding environment, the conductor temperature will rise. Simultaneously, because the ambient temperature is relatively low, creating a temperature difference, heat will diffuse outwards from the high-temperature area.

[0106] The formula for heat diffusion in a conductor is: Q = (T1 - T2)t / R, and the formula for calculating the temperature rise of the conductor is: T1 - T2 = I. 2 rR, where T1 represents the temperature rating of the conductor in °C, T2 represents the ambient temperature of the conductor in °C, I represents the rated current passing through the conductor in amperes (A), r represents the thermal resistance of the conductor at a certain temperature in ohms (Ω), and R represents the thermal resistance of the conductor in °C·m / W.

[0107] The current that the conductor can withstand at its maximum permissible operating temperature is:

[0108] The formula for calculating the DC resistance r of a conductor is: r = r20[1 + 0.003939(T1 - 20°)], where r20 represents the DC resistance of the conductor at 20°C, and the unit is Ω / m.

[0109] Calculation of AC resistance r1 of a conductor: The AC resistance of a conductor at its highest temperature is usually given by the following formula: r1 = r(1 + ys + yp), where ys represents the skin effect factor and yp represents the proximity effect factor. Where: f is the power supply frequency, k s See Table 3 below. Considering the layout environment of electric vehicles, yp can be ignored.

[0110] Table 3

[0111] Wire type Ks Kp Twisted wire 1 0.8 Tightly pressed round strand 1 0.8 Dividing circle line 0.435 0.37 Spiral strand 0.9 0.8 sector line 1 0.8

[0112] In calculating the thermal resistance of a conductor, the thermal resistance comprises two parts: the thermal resistance of the conductor itself and the external thermal resistance. The thermal resistance of the conductor itself depends on the conductor's structure and the thermal resistivity of its materials. It generally consists of the thermal resistance per unit length of the conductor insulation (R1), the thermal resistance per unit length of the inner lining layer (R2), the thermal resistance per unit length of the sheath (R3), and the thermal resistance per unit length between the conductor surface and the surrounding medium (R4).

[0113] R = R1 + n[(1 + λ1)R2 + (1 + λ1 + λ2)R2 + R3], where n is the number of current-carrying conductors, λ1 is the ratio of the inner sheath loss to the total loss of all conductors, and λ2 is the ratio of the outer sheath loss to the total loss of all conductors. λ1 and λ2 are only used for AC calculations.

[0114] The thermal resistance R1 of the insulation layer can be calculated using the following formula: Where R1 represents the thermal resistance per unit length of insulation, ρ T The value represents the thermal resistance coefficient of the insulating material, D1 represents the outer diameter of the insulation in mm, and d1 represents the outer diameter of the conductor.

[0115] The thermal resistivity of the insulating material can be referenced in Table 4 below.

[0116] Table 4

[0117]

[0118]

[0119] The thermal resistance R2 of the inner lining can be calculated using the following formula: Where R2 represents the thermal resistance of the liner, ρ TD1 represents the thermal resistance coefficient of the insulation material, D2 represents the outer diameter of the inner lining layer in mm, and d2 represents the outer diameter of the multi-core insulation.

[0120] The thermal resistance R3 of the sheath layer can be calculated using the following formula: Where R3 represents the thermal resistance per unit length of the sheath, ρ T D3 represents the thermal resistance coefficient of the insulation material, D3 represents the outer diameter of the sheath in mm, and d3 represents the outer diameter of the shield.

[0121] The thermal resistance R4 of the conductor surface can be calculated using the following formula: Where R4 represents the thermal resistance of the conductor surface and D3 represents the outer diameter of the sheath, in mm.

[0122] Calculations are performed to determine whether the conductor meets the load-carrying requirements.

[0123] Figure 8 This is a schematic diagram of the matching curve between the conductor and the fuse. For example... Figure 8 As shown, under the same current conditions, the smoke emission time of the conductor should be longer than the melting time of the fuse.

[0124] Step S4: Based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, perform an overcurrent matching check to determine whether the overcurrent matching check passes. If it does, perform a temperature rise check.

[0125] In some optional implementations of this embodiment, step S4, based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, performs an overcurrent matching check and determines whether the overcurrent matching check passes. If it does, a temperature rise check is performed. This may further include the following steps:

[0126] S41. Determine the characteristics of the fuse.

[0127] Before determining the characteristics of a fuse, a database of characteristics for various types of fuses can be established. When it is necessary to determine the characteristics of a fuse, the fuse model can be used as the search keyword to search the database and obtain the fuse characteristics, including its rated current, fusing current and other key parameters.

[0128] S42. Analyze system overcurrent.

[0129] Based on the system's design and operating conditions, analyze the maximum possible overcurrent.

[0130] S43. Current matching judgment.

[0131] The fusing current of the fuse is compared with the maximum possible overcurrent in the system. If the fusing current is greater than or equal to the maximum overcurrent, the overcurrent matching check is considered to have passed.

[0132] Step S5: Determine whether the temperature rise check passes. If it does, proceed to the smoke generation time check; otherwise, proceed to step S3.

[0133] In some optional implementations of this embodiment, step S5, determining whether the temperature rise verification passes, if yes, then performing a smoke generation time verification; otherwise, proceeding to step S3, may further include the following steps:

[0134] S51. Determine the operating current of the circuit based on the design and operating conditions of the electrical system. S52. Obtain the DC resistance and thermal resistance parameters of the conductors.

[0135] Before obtaining the DC resistance and thermal resistance parameters of a conductor, a database of these parameters can be established based on different conductor types. When the DC resistance and thermal resistance parameters of a conductor are needed, the conductor type can be used as a keyword to search the database and obtain the relevant parameters.

[0136] S53. Substitute the known operating current, DC resistance of the conductor, and thermal resistance parameters into the formula to perform calculations. Based on the calculation results, evaluate whether the temperature rise of the circuit meets the requirements.

[0137] If the temperature rise in the circuit is lower than the temperature that the conductor can withstand, the temperature rise check is considered to have passed.

[0138] Smoke generation time under overload conditions: During the operation of electrical appliances (e.g., inductive loads), there are pulse currents and surge currents. When the current passing through the conductor is higher than its rated current, it is necessary to determine whether the smoke generation time of the conductor is greater than the fuse blowing time, and the impact on the aging of the conductor itself. Figure 9 This is a schematic diagram showing the smoke generation time under conductor overload current, as shown below. Figure 9 As shown, under the same conditions, the fuse breaking current should be less than the clearance overcurrent at the start of smoke in the conductor. The required time must be less than the time it takes for the conductor to start smoking; this design theory is consistent with low-voltage lines. By using the electrical parameter attribute table of the appliance, the overload percentage and duration that the fuse can withstand are determined, and the time and clearance overcurrent that cause the conductor to smoke under overload conditions are calculated.

[0139] The formula for calculating the smoke generation time under conductor overload current is as follows: T1 - T2 = I 2 rR(1-e-at), where, Where t is the time when smoke begins to appear, T1 is the conductor temperature at the time of smoke appearance, and a is the reciprocal of the thermal constant. Q is the heat capacity, Q = ncSa, Sa is the cross-sectional area of ​​the conductor, and c is the heat capacity coefficient of the conductor.

[0140] Step S6: Determine whether the smoke generation time verification is passed. If so, conduct electrical performance testing for confirmation.

[0141] In some optional implementations of this embodiment, step S6, determining whether the smoke generation time verification passes, and if so, performing electrical performance testing for confirmation, may further include the following steps:

[0142] S61. Determine the conductor temperature when the wire emits smoke.

[0143] The smoking temperature of a conductor is usually a specific temperature threshold. When the temperature of the conductor reaches or exceeds this threshold, the conductor may begin to smoke.

[0144] S62. Confirm the thermal constant of the conductor.

[0145] The thermal constant of a conductor is a parameter that describes the thermal response characteristics of a conductor. It involves factors such as the thermal conductivity, heat capacity, and heat exchange with the surrounding environment of the conductor material.

[0146] S63. Based on the known smoke temperature and thermal constant of the conductor, calculate the time required for the conductor to reach the smoke temperature.

[0147] If the smoke emission time of the circuit is less than the conductor's withstand time, the smoke emission time check is considered to have passed.

[0148] The beneficial effects of implementing this embodiment are as follows: it comprehensively considers multiple aspects such as the performance of electrical components, environmental factors, and frequency factors, including temperature, heat conduction, and air cooling factors, ensuring the accuracy and reliability of the high-voltage system during the design process; it can effectively avoid failure risks, improve the safety and stability of the system, and provide strong support for the development of automotive electrification; at the same time, it also has strong operability and practicality, and can provide useful reference and guidance for the circuit matching design of high-voltage systems.

[0149] This invention can be used in a wide variety of general-purpose or special-purpose computer system environments or configurations. Examples include: personal computers, server computers, handheld or portable devices, tablet devices, multiprocessor systems, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, and distributed computing environments including any of the above systems or devices. This invention can be described in the general context of computer-executable instructions, such as program modules, that are executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific tasks or implement specific abstract data types. This invention can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0150] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by instructing related hardware with computer-readable instructions. These computer-readable instructions can be stored in a computer-readable storage medium. When executed, the program can include the processes of the embodiments of the above methods. The aforementioned storage medium can be a non-volatile storage medium such as a magnetic disk, optical disk, or read-only memory (ROM), or random access memory (RAM).

[0151] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the flowcharts of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0152] Example 2

[0153] This embodiment uses high-voltage electrical equipment as an example for illustration. The electrical parameters are shown in Table 5:

[0154] Table 5

[0155]

[0156] The first step is to select the appropriate fuse.

[0157] The rated operating current of the electrical equipment is 21A. According to the fuse selection method:

[0158] If≥In / (Kt×Ke×Kv×Kf)=21 / 0.9*0.85*1*1=27.45A;

[0159] Therefore, the Little 30A high-voltage fuse was initially selected.

[0160] Relative to I 2 Verification: During compressor operation, pulse currents occur, and the fuse must withstand a sufficient number of pulses. Therefore, a relative I is introduced. 2 t = pulse current I 2 t / fuse breaking current I 2 The impact of t on insured life is shown in Table 6.

[0161] Pulse current I 2 t = 602 * 0.0001 = 0.36. For 30A insurance, according to Table 6, I... 2 t = 993. Relative to I²t = 0.36 / 993 = 0.03%, it can withstand more than 1,000,000 impacts.

[0162] Table 6

[0163] Fuse capacity <![CDATA[Life curve (A2S)]]> 10A 255 15A 133 20A 268 30A 993 40A 1495

[0164] Overload verification: According to the electrical parameters, there is a peak current of 60A during the operation of the electric compressor, which lasts for 100μS. Under 200% overload (see Table 7 below), the fuse blows in a minimum of 0.5s, which is much longer than the operating duration of the compressor and meets the design requirements.

[0165] Table 7

[0166]

[0167] The second step is to select the appropriate wire type.

[0168] Based on the electrical parameters, the maximum continuous operating current of the compressor is 31A. According to the selection principle, a 2×2.5mm² multi-core double-layer shielded wire (temperature resistance rating 180℃) is initially selected.

[0169] (1) Calculation of relevant parameter values

[0170] ① DC resistance of conductor

[0171] r = r20[1 + 0.003939(T1 - 20°)]

[0172] =0.0078×[1+0.00393(180-20)]=0.0127Ω.

[0173] ② Thermal resistance of insulation layer R1

[0174]

[0175] ③Inner lining thermal resistance R2

[0176]

[0177] ④ Thermal resistance of the sheath layer R3

[0178]

[0179] ⑤ Calculation of surface heat dissipation thermal resistance R4

[0180]

[0181] The thermal resistance of a conductor is R = R1 + n[(1 + λ1)R2 + (1 + λ1 + λ2)R2 + R3]

[0182] =24.68+2×(74.80+19.33+195.48)=603.9(Ω).

[0183] (2) Calculation of rated current carrying capacity of cable

[0184] ① When the ambient temperature of the conductor is 60℃, the current that the cable can carry is:

[0185]

[0186] ② When the ambient temperature of the conductor is 90℃, the current that the cable can withstand is:

[0187]

[0188] ③ When the ambient temperature of the conductor is 120℃, the current that the cable can withstand is:

[0189]

[0190] (3) Temperature rise calculation

[0191] When electrical equipment is in continuous operation, the temperature rise of the conductor is as follows:

[0192] The temperature rise requirement is met.

[0193] (4) Overload verification

[0194] During operation, the compressor's peak operating current is 60A for 100μS, while the fuse's longest blowing time under 200% overload is 100s.

[0195] Therefore, the smoke generation time of a 2×2.5mm² wire under a 60A peak current is:

[0196]

[0197] The relevant parameters for calculating 2×2.5mm² multi-core conductors are as follows:

[0198]

[0199] It is evident that the smoke emission time of the conductor under overload is 66.13 seconds, which does not meet the design requirements. Therefore, a 2×4mm² cross-sectional area conductor needs to be selected for further design verification.

[0200] (5) Select a 2×4mm² cross-sectional area wire.

[0201] ① DC resistance of conductor

[0202] r = r20[1 + 0.00393(T1 - 20℃)]

[0203] =0.0048×[1+0.00393(180-20)]=0.00781Ω.

[0204] ② Thermal resistance of insulation layer R1

[0205]

[0206] ③Inner lining thermal resistance R2

[0207]

[0208] ④ Thermal resistance of the sheath layer R3

[0209]

[0210] ⑤ Calculation of surface heat dissipation thermal resistance R3

[0211]

[0212] The thermal resistance of a conductor is R = R1 + n[(1 + λ1)R2 + (1 + λ1 + λ2)R2 + R3]

[0213] =20.65+2×(81.93+7.44+187.12)=573.63(Ω).

[0214] ⑥ Overload verification

[0215] 2×4mm 2 The smoke emission time of a conductor with a wire diameter of 60A under peak current conditions is as follows:

[0216]

[0217]

[0218] The relevant parameters for calculating 2×4mm² multi-core conductors are as follows:

[0219]

[0220] The beneficial effects of implementing this embodiment are: it comprehensively considers multiple aspects such as the performance of electrical components, environmental factors, and frequency factors, ensuring the accuracy and reliability of the high-voltage system during the design process; it can effectively avoid failure risks, improve the safety and stability of the system, and provide strong support for the development of automotive electrification; at the same time, it also has strong operability and practicality, and can provide useful reference and guidance for the circuit matching design of high-voltage systems.

[0221] Example 3

[0222] Further reference Figure 10 As a response to the above Figure 1 The present invention provides an embodiment of a system loop matching design device for the implementation of the method shown, which is similar to... Figure 1 Corresponding to the method embodiments shown, this device can be specifically applied to various electronic devices.

[0223] like Figure 10 As shown, the system loop matching design device 70 described in this embodiment includes: an acquisition module 71, a calculation module 72, a selection module 73, a first verification module 74, a second verification module 75, and a confirmation module 76. Wherein:

[0224] Module 71 is used to acquire load parameters in the system loop;

[0225] Calculation module 72 is used to calculate the load current based on the load parameters;

[0226] Selection module 73 is used to select a fuse, define the temperature rating, and select the cable diameter based on the load current.

[0227] The first verification module 74 is used to perform overcurrent matching verification based on the selected fuse, the defined temperature resistance rating and the selected cable diameter, and to determine whether the overcurrent matching verification passes. If it does, the temperature rise verification is performed.

[0228] The second verification module 75 is used to determine whether the temperature rise verification passes; if so, the smoke generation time verification is performed.

[0229] The confirmation module 76 is used to determine whether the smoke generation time verification has passed. If it has, the electrical performance test is performed for confirmation.

[0230] The system loop matching design device 70 described in this embodiment can, for example, Figure 2 Implemented on the system architecture shown. For example... Figure 2As shown, the system architecture includes a PDU (Power Distribution Unit), a power battery module electrically connected to the PDU, a DC charging port, an on-board charger, a PTC heater, an electric compressor, a motor controller, fuses, wires, and electrical equipment. The PDU is responsible for power distribution and management in the high-voltage system solution. It connects high-voltage components electrically through busbars and wiring harnesses, ensuring the normal operation of the vehicle's high-voltage system. The main functions of the PDU include charge / discharge control, high-voltage component power-on control, circuit overload and short-circuit protection, high-voltage sampling, and low-voltage control. These functions work together to protect and monitor the operation of the high-voltage system, ensuring the vehicle operates safely and stably under various conditions. Fuses melt and cut off the current when the current abnormally rises to a certain level and temperature, thus protecting the circuit's safe operation. Wires are the carriers of current transmission, responsible for effectively transmitting the electrical energy generated by the power source to various electrical devices, ensuring the normal operation of the entire circuit system. Electrical equipment is responsible for executing vehicle functions.

[0231] The beneficial effects of implementing this embodiment are: it comprehensively considers multiple aspects such as the performance of electrical components, environmental factors, and frequency factors, ensuring the accuracy and reliability of the high-voltage system during the design process; it can effectively avoid failure risks, improve the safety and stability of the system, and provide strong support for the development of automotive electrification; at the same time, it also has strong operability and practicality, and can provide useful reference and guidance for the circuit matching design of high-voltage systems.

[0232] Example 4

[0233] To address the aforementioned technical problems, embodiments of the present invention also provide a computer device. Please refer to [link / reference needed]. Figure 11 , Figure 11 This is a basic structural block diagram of the computer device in this embodiment.

[0234] The aforementioned computer device 8 includes a memory 81, a processor 82, and a network interface 83 that are interconnected via a system bus. It should be noted that only the computer device 8 with components 81, 82, and 83 is shown in the figure; however, it should be understood that it is not required to implement all the shown components, and more or fewer components can be implemented alternatively. Those skilled in the art will understand that the computer device described herein is a device capable of automatically performing numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes, but is not limited to, microprocessors, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), embedded devices, etc.

[0235] The aforementioned computer devices can be desktop computers, laptops, handheld computers, and cloud servers, among other computing devices. These devices can facilitate human-computer interaction with users through keyboards, mice, remote controls, touchpads, or voice-activated devices.

[0236] The aforementioned memory 81 includes at least one type of readable storage medium, including flash memory, hard disk, multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic memory, magnetic disk, optical disk, etc. In some embodiments, the aforementioned memory 81 may be an internal storage unit of the aforementioned computer device 8, such as the hard disk or memory of the computer device 8. In other embodiments, the aforementioned memory 81 may also be an external storage device of the aforementioned computer device 8, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the computer device 8. Of course, the aforementioned memory 81 may also include both the internal storage unit and its external storage device of the aforementioned computer device 8. In this embodiment, the aforementioned memory 81 is typically used to store the operating system and various application software installed on the aforementioned computer device 8, such as computer-readable instructions for system loop matching design methods, etc. In addition, the aforementioned memory 81 can also be used to temporarily store various types of data that have been output or will be output.

[0237] In some embodiments, the processor 82 described above may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. The processor 82 is typically used to control the overall operation of the computer device 8. In this embodiment, the processor 82 is used to execute computer-readable instructions stored in the memory 81 or to process data, for example, to execute computer-readable instructions of the system loop matching design method described above.

[0238] The network interface 83 may include a wireless network interface or a wired network interface, which is typically used to establish a communication connection between the computer device 8 and other electronic devices.

[0239] The beneficial effects of implementing this embodiment are: it comprehensively considers multiple aspects such as the performance of electrical components, environmental factors, and frequency factors, ensuring the accuracy and reliability of the high-voltage system during the design process; it can effectively avoid failure risks, improve the safety and stability of the system, and provide strong support for the development of automotive electrification; at the same time, it also has strong operability and practicality, and can provide useful reference and guidance for the circuit matching design of high-voltage systems.

[0240] Example 5

[0241] The present invention also provides another embodiment, namely, providing a computer-readable storage medium storing computer-readable instructions that can be executed by at least one processor to cause the at least one processor to perform the steps of the system loop matching design method described above.

[0242] The beneficial effects of implementing this embodiment are: it comprehensively considers multiple aspects such as the performance of electrical components, environmental factors, and frequency factors, ensuring the accuracy and reliability of the high-voltage system during the design process; it can effectively avoid failure risks, improve the safety and stability of the system, and provide strong support for the development of automotive electrification; at the same time, it also has strong operability and practicality, and can provide useful reference and guidance for the circuit matching design of high-voltage systems.

[0243] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0244] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A system loop matching design method, characterized in that, Includes the following steps: S1. Obtain the load parameters in the system loop; S2. Calculate the load current based on the load parameters; S3. Select a fuse, define the temperature rating, and select the cable diameter based on the load current. S4. Based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, perform overcurrent matching verification to determine whether the overcurrent matching verification passes. If it does, then perform temperature rise verification. S5. Determine whether the temperature rise check passes. If yes, proceed to the smoke generation time check; otherwise, proceed to step S3. S6. Determine whether the smoke emission time verification is passed. If so, conduct electrical performance testing for confirmation.

2. The system loop matching design method according to claim 1, characterized in that, The step S1, obtaining the load parameters in the system loop, specifically includes: S11. Determine the load type; S12. Confirm the circuit operating current; S13. The measured and confirmed load type, operating current, stall current, and stall time parameters are incorporated into the ICD table to achieve load parameter management.

3. The system loop matching design method according to claim 1, characterized in that, The step S2, calculating the load current based on the load parameters, specifically includes: S21. Calculate the ratio of rated power to nominal voltage to obtain the first ratio; S22. Calculate the ratio of the actual voltage to the nominal voltage to obtain the second ratio; S23. The product of the first ratio and the second ratio is the load current.

4. The system loop matching design method according to claim 1, characterized in that, The steps S3, which involve selecting a fuse, defining its temperature rating, and selecting the cable diameter based on the load current, specifically include: S31. Based on the load current, select a fuse with a rated current greater than the load current; S32. Select the temperature resistance rating of the conductor according to the characteristics of the working environment; S33. Select the conductor diameter based on the assessment results of circuit temperature rise and conductor smoke risk.

5. The system loop matching design method according to claim 1, characterized in that, S4, based on the selected fuse, the defined temperature resistance rating, and the selected cable diameter, performs an overcurrent matching check to determine whether the overcurrent matching check passes. If it does, the temperature rise check is then performed. The specific steps include: S41. Determine the characteristics of the fuse; S42. Analyze system overcurrent; S43. Current matching judgment.

6. The system loop matching design method according to claim 1, characterized in that, Step S5, determining whether the temperature rise verification passes, proceeds to the smoke generation time verification if it does; otherwise, it proceeds to step S3. The specific steps include: S51. Determine the operating current of the circuit based on the design and operating conditions of the electrical system; S52. Obtain the DC resistance and thermal resistance parameters of the conductor; S53. Substitute the known operating current, DC resistance of the conductor, and thermal resistance parameters into the formula to perform calculations. Based on the calculation results, evaluate whether the temperature rise of the circuit meets the requirements.

7. The system loop matching design method according to any one of claims 1 to 6, characterized in that, The step S6, determining whether the smoke generation time verification passes and then proceeding with electrical performance testing for confirmation, specifically includes: S61. Determine the conductor temperature when the wire emits smoke; S62. Confirm the thermal constant of the conductor; S63. Based on the known smoke temperature and thermal constant of the conductor, calculate the time required for the conductor to reach the smoke temperature.

8. A system loop matching design device, characterized in that, include: The acquisition module is used to acquire load parameters in the system loop; The calculation module is used to calculate the load current based on the load parameters; The selection module is used to select a fuse, define the temperature rating, and select the cable diameter based on the load current. The first verification module is used to perform overcurrent matching verification based on the selected fuse, the defined temperature resistance rating and the selected cable diameter, and to determine whether the overcurrent matching verification passes. If it does, the temperature rise verification is performed. The second verification module is used to determine whether the temperature rise verification passes; if it does, the smoke generation time verification is performed. The confirmation module is used to determine whether the smoke emission time verification has passed. If so, electrical performance testing is performed for confirmation.

9. A computer device comprising a memory and a processor, the memory storing computer-readable instructions, wherein the processor, when executing the computer-readable instructions, implements the steps of the system loop matching design method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-readable instructions, which, when executed by a processor, implement the steps of the system loop matching design method as described in any one of claims 1 to 7.

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