A modeling method and system for describing the electro-thermal coupling characteristics of a power device-heat sink

Abstract

The application discloses a modeling method and system for describing power device-radiator electrothermal coupling characteristics, and relates to the technical field of converters.The modeling method comprises the following steps: calculating the average power loss of a power device in a power grid cycle based on a pre-set main circuit model of a converter; calculating the total thermal resistance of the power device from a junction to an environment based on a pre-set three-dimensional thermal network model of the power device; initializing the environment temperature, and combining the average power loss of the power device in the power grid cycle and the total thermal resistance of the power device from the junction to the environment to calculate a steady-state junction temperature; based on the steady-state junction temperature, updating electrical parameters according to the nonlinear characteristics of the electrical parameters related to the temperature of the power device changing with the temperature; updating the main circuit model of the converter according to the updated electrical parameters, and closing loop and iterating until the electrothermal coupling converges, thereby completing the modeling.The application can significantly improve the modeling precision, has good universality, and can be widely applied to the reliability design of power devices, and guarantees the safe operation of the power devices.

Description

Technical Field

[0001] This invention relates to the field of converter technology, and in particular to a modeling method and system for describing the electrothermal coupling characteristics of power devices and heat sinks. Background Technology

[0002] As new energy power generation systems develop towards larger capacity and higher efficiency, the power density of power electronic equipment such as wind power converters and photovoltaic inverters continues to increase, leading to increasingly harsh operating environments for power devices. Statistics show that temperature accounts for as much as 55% of electronic product failures, making it the primary factor affecting system reliability. High temperatures not only cause semiconductor material performance degradation and accelerate insulation aging, but also trigger dust accumulation, further reducing heat dissipation efficiency and creating a vicious cycle of "temperature rise—failure."

[0003] Currently, most mainstream heat dissipation designs employ static thermal analysis methods, which assume that the electrical parameters of power devices, such as on-resistance and switching losses, are constant, and perform thermal simulations based solely on rated current or average power consumption. However, in actual operation, the on-resistance of power devices exhibits a significant positive temperature coefficient. As the junction temperature rises, the on-resistance increases, leading to additional Joule heat generation and further exacerbating the temperature rise. If this electrothermal coupling effect is not considered, traditional thermal models will severely underestimate the actual junction temperature, resulting in conservative heat dissipation design or the risk of overheating.

[0004] Furthermore, in the actual operation of power electronic equipment such as wind power converters, bridge arm failures are inevitable. Existing fault-tolerant control strategies typically only retain some healthy devices to continue operating, neglecting the potential for reuse of still usable healthy devices and heat sink resources in the failed bridge arm. For example, after a failure in one bridge arm, the power devices in the remaining arms can still continue to operate, but current needs to be redistributed to avoid overload. However, how to fully utilize these redundant resources to improve the fault-tolerant operating capacity of the system while ensuring that devices are not overloaded has become an urgent technical challenge. To this end, it is necessary to establish a dynamic model that can accurately reflect the interaction between electrical behavior and thermal field distribution.

[0005] Although some studies have attempted to use the finite element method for co-simulation of electrothermal processes, most are limited to specific device types and lack a generalized modeling framework. Existing methods typically rely on complex integrated simulation tools, which restricts the flexibility and scalability of engineering applications. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a modeling method and system for describing the electrothermal coupling characteristics of power devices and heat sinks. This method and system can achieve high-precision thermal analysis and reliability assessment of power devices and heat sinks, and can be applied to the reliability design of power devices to ensure their safe operation.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0008] In a first aspect, the present invention provides a modeling method for describing the electrothermal coupling characteristics of a power device-heat sink, comprising:

[0009] The average power loss of power devices over one grid cycle is calculated based on a pre-set converter main circuit model.

[0010] The total thermal resistance of the power device from junction to environment is calculated based on a pre-set three-dimensional thermal network model of the power device.

[0011] Initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device over one power grid cycle and the total thermal resistance of the power device from the junction to the environment;

[0012] Based on the steady-state junction temperature, the electrical parameters are updated according to the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature.

[0013] The converter main circuit model is updated based on the updated electrical parameters, and the closed-loop iteration continues until the electrothermal coupling converges, thus completing the modeling.

[0014] Optionally, the main circuit model of the converter is constructed using PSpice software, including a DC power supply, a three-phase inverter, and a three-phase filter connected in sequence, wherein the three-phase inverter includes power devices.

[0015] Optionally, the calculation of the average power loss of the power device within one grid cycle based on the pre-set converter main circuit model includes:

[0016] Instantaneous current and voltage signals on power devices are obtained based on a pre-set converter main circuit model;

[0017] The instantaneous power loss of the power device is calculated based on the instantaneous current and voltage signals;

[0018] The average power loss of the power device over one power grid cycle is calculated based on the instantaneous power loss of the power device. :

[0019]

[0020] In the formula, For power devices at time Power loss, For the power grid cycle.

[0021] Optionally, the steady-state junction temperature is:

[0022]

[0023] In the formula, For steady-state junction temperature and ambient temperature, This refers to the average power loss of a power device over one power grid cycle. The total thermal resistance from junction to environment;

[0024]

[0025] In the formula, The thermal resistance from junction to shell, This refers to the thermal resistance from the shell to the environment.

[0026] Optionally, the three-dimensional thermal network model of the power device is constructed using Icepak software, including a junction-to-case thermal resistance model and a case-to-ambient thermal resistance model.

[0027] Obtain the physical dimensions and thermal conductivity of the silicon chip and package of the power device, construct a junction-to-case thermal resistance model based on the law of thermal conduction, and calculate the junction-to-case thermal resistance. ;

[0028] Obtain the thermal grease between the power device's package and the heatsink, the heatsink's physical dimensions and thermal conductivity, construct a thermal resistance model from the package to the environment based on the law of thermal conduction, and calculate the thermal resistance from the package to the environment. .

[0029] Optionally, the law of heat conduction is Fourier's law:

[0030]

[0031] In the formula, The heat transfer flux is in the direction of heat conduction. Let be the cross-sectional area of ​​the heat-conducting medium perpendicular to the direction of heat conduction. The thermal conductivity of the heat-conducting medium. The distance in the direction of heat conduction. For temperature, The temperature gradient is along the direction of heat conduction.

[0032]

[0033] In the formula, These are the temperatures of the hot isotherm and the cold isotherm, respectively. The temperature difference between a thermal isotherm and a cold isotherm. The length of the heat conduction medium in the direction of heat conduction. This is the equivalent thermal resistance.

[0034] Secondly, the present invention provides a modeling system for describing the electrothermal coupling characteristics of a power device-heat sink, comprising:

[0035] The power consumption calculation module is configured to calculate the average power loss of power devices over a power grid cycle based on a pre-set converter main circuit model.

[0036] The thermal resistance calculation module is configured to calculate the total thermal resistance of the power device from the junction to the environment based on a pre-set three-dimensional thermal network model of the power device.

[0037] The junction temperature calculation module is configured to initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device in one power grid cycle and the total thermal resistance of the power device from the junction to the environment.

[0038] The parameter update module is configured to update the electrical parameters based on the steady-state junction temperature and according to the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature.

[0039] The iterative modeling module is configured to update the converter main circuit model based on the updated electrical parameters, and iterate in a closed loop until the electrothermal coupling converges, thus completing the modeling.

[0040] Thirdly, the present invention provides an electronic device, including a processor and a storage medium;

[0041] The storage medium is used to store instructions;

[0042] The processor is configured to operate according to the instructions to perform the steps according to the method described above.

[0043] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0044] Fifthly, the present invention provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the steps of the above-described method.

[0045] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0046] This invention provides a modeling method and system for describing the electrothermal coupling characteristics of power devices and heat sinks. Through a closed-loop iterative mechanism of "circuit simulation—thermal simulation—junction temperature feedback," it effectively solves the problem of neglecting the temperature-dependent changes in device electrical parameters in traditional thermal analysis, avoids Joule heating misjudgments caused by increased on-resistance, and significantly improves the accuracy of thermal simulation. The established model has good versatility, adaptable to various power devices, and suitable for converter systems with different topologies. It can realistically reflect the positive feedback vicious cycle of "increased junction temperature → increased on-resistance → increased losses → further increase in junction temperature," providing a more reliable basis for the thermal design of high-power-density equipment. In the fault-tolerant operation scenario of wind power converters, it can be used to assess the safety margin of healthy devices in a faulty arm under high-temperature conditions, guide the rational allocation and reuse of heat sink resources, and improve system fault tolerance capacity and power generation efficiency. Attached Figure Description

[0047] Figure 1 This is a schematic flowchart of a modeling method for describing the electrothermal coupling characteristics of a power device-heat sink, provided in an embodiment of the present invention.

[0048] Figure 2 This is a simulation diagram illustrating the electrothermal coupling characteristics of a power device and a heat sink, provided by an embodiment of the present invention.

[0049] Figure 3 This is a schematic diagram of the heat conduction process provided in an embodiment of the present invention;

[0050] Figure 4 This is a schematic diagram of a typical assembly method for the power device provided in an embodiment of the present invention;

[0051] Figure 5 This is a schematic diagram illustrating the relationship between normalized on-resistance and temperature provided in an embodiment of the present invention;

[0052] Figure 6 This is a schematic diagram of a thermal imaging of an electrothermal coupling simulation radiator provided in an embodiment of the present invention. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0054] Example 1:

[0055] like Figure 1 As shown, this embodiment of the invention provides a modeling method for describing the electrothermal coupling characteristics of a power device-heat sink, including the following steps:

[0056] Step S1: Calculate the average power loss of the power devices over one grid cycle based on the pre-set converter main circuit model. Specifically, this includes:

[0057] Step S1.1: Obtain the instantaneous current and voltage signals on the power devices based on the pre-set converter main circuit model;

[0058] Step S1.2: Calculate the instantaneous power loss of the power device based on the instantaneous current and voltage signals;

[0059] Step S1.3: Calculate the average power loss of the power device over one power grid cycle based on the instantaneous power loss of the power device. :

[0060]

[0061] In the formula, For power devices at time Power loss, For the power grid cycle.

[0062] Specifically, in this embodiment, the main circuit model of the converter is constructed using PSpice software, including a DC power supply, a three-phase inverter, and a three-phase filter connected in sequence. The three-phase inverter includes power devices.

[0063] Power devices include, but are not limited to, any one or more power semiconductor devices such as MOSFET, IGBT, and SCR.

[0064] Step S2: Calculate the total thermal resistance of the power device from the junction to the environment based on the pre-set three-dimensional thermal network model of the power device.

[0065] like Figure 4 The diagram shows a typical assembly method for power devices. The power devices are mounted on a PCB board and cooled by a heat sink. The temperature is conducted from the junction to the environment, through the silicon chip, package, thermal grease, and heat sink to the environment.

[0066] Specifically, in this embodiment, the three-dimensional thermal network model of the power device is constructed using Icepak software, including a junction-to-case thermal resistance model and a case-to-ambient thermal resistance model.

[0067] Obtain the physical dimensions and thermal conductivity of the silicon chip and package of the power device, construct a junction-to-case thermal resistance model based on the law of thermal conduction, and calculate the junction-to-case thermal resistance. ;

[0068] Obtain the thermal grease between the power device's package and the heatsink, the heatsink's physical dimensions and thermal conductivity, construct a thermal resistance model from the package to the environment based on the law of thermal conduction, and calculate the thermal resistance from the package to the environment. .

[0069] like Figure 3As shown, the law of heat conduction adopts Fourier's law:

[0070]

[0071] In the formula, The heat transfer flux is in the direction of heat conduction. Let be the cross-sectional area of ​​the heat-conducting medium perpendicular to the direction of heat conduction. The thermal conductivity of the heat-conducting medium. The distance in the direction of heat conduction. For temperature, The temperature gradient is along the direction of heat conduction.

[0072]

[0073] In the formula, These are the temperatures of the hot isotherm and the cold isotherm, respectively. The temperature difference between a thermal isotherm and a cold isotherm. The length of the heat conduction medium in the direction of heat conduction. This is the equivalent thermal resistance.

[0074] Step S3: Initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device in one power grid cycle and the total thermal resistance of the power device from the junction to the environment.

[0075] The steady-state junction temperature is:

[0076]

[0077] In the formula, For steady-state junction temperature and ambient temperature, This refers to the average power loss of a power device over one power grid cycle. The total thermal resistance from junction to environment;

[0078]

[0079] In the formula, The thermal resistance from junction to shell, This refers to the thermal resistance from the shell to the environment.

[0080] Step S4: Based on the steady-state junction temperature, update the electrical parameters according to the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature.

[0081] Temperature-dependent electrical parameters of power devices, such as on-resistance, exhibit non-linear characteristics that vary with temperature. These characteristics are derived from technical manuals or measured data provided by the power device manufacturer. Specifically, the non-linearity of on-resistance with temperature is expressed as the normalized on-resistance R. on With junction temperature T jThe functional relationship, such as Figure 5 As shown.

[0082] from Figure 5 It can be seen that, taking the on-resistance at 25℃ as a reference, the on-resistance exhibits a non-linear increasing trend with rising junction temperature. When the junction temperature reaches 80℃, the on-resistance has increased to 1.5 times the reference value; when the junction temperature reaches 130℃, the on-resistance is close to twice the reference value. This characteristic indicates that, under high-temperature conditions, ignoring the change in on-resistance will lead to misjudgment of Joule heating, thus affecting the accuracy of thermal simulation. Therefore, this temperature dependence must be incorporated into the electrothermal coupling model.

[0083] Step S5: Update the converter main circuit model according to the updated electrical parameters, and iterate in a closed loop until the electrothermal coupling converges to complete the modeling.

[0084] Figure 6 This is a schematic diagram of the thermal imaging of a heat sink simulated by electrothermal coupling according to an embodiment of the present invention. After multiple rounds of electrothermal coupling iterations, the final temperature field distribution on the heat sink surface is shown in the figure. The highest temperature is located in the dense MOSFET device area, reaching 73.03℃, and the temperature gradually decreases from the center to the periphery, which conforms to the thermal diffusion law.

[0085] In practical applications, the method of this invention can be used to evaluate the reuse of healthy device resources in fault-tolerant operation scenarios of wind power converters. For example, after a failure in one arm, healthy MOSFETs in the remaining arms can continue to operate, but current needs to be redistributed to avoid overload. Using the electrothermal coupling model proposed in this invention, the junction temperature changes of these devices under high loads can be accurately predicted, ensuring they do not exceed their safe operating range, thereby improving system fault tolerance and power generation efficiency.

[0086] Example 2

[0087] This invention provides a modeling system for describing the electrothermal coupling characteristics of power devices and heat sinks, comprising:

[0088] The power consumption calculation module is configured to calculate the average power loss of power devices over a power grid cycle based on a pre-set converter main circuit model.

[0089] The thermal resistance calculation module is configured to calculate the total thermal resistance of the power device from the junction to the environment based on a pre-set three-dimensional thermal network model of the power device.

[0090] The junction temperature calculation module is configured to initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device over one power grid cycle and the total thermal resistance of the power device from the junction to the environment.

[0091] The parameter update module is configured to update the electrical parameters based on the steady-state junction temperature and the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature.

[0092] The iterative modeling module is configured to update the converter main circuit model based on the updated electrical parameters, and iterate in a closed loop until the electrothermal coupling converges, thus completing the modeling.

[0093] Example 3

[0094] Based on the modeling method provided in Embodiment 1, this embodiment of the invention provides an electronic device, including a processor and a storage medium;

[0095] Storage media are used to store instructions;

[0096] The processor is used to perform operations according to instructions to execute the steps according to the method described above.

[0097] Example 4

[0098] Based on the modeling method provided in Embodiment 1, this embodiment of the invention provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0099] Example 5

[0100] Based on the modeling method provided in Embodiment 1, this embodiment of the invention provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the above-described method.

[0101] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0103] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0104] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0105] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A modeling method for describing the electrothermal coupling characteristics of a power device-heat sink, characterized in that, include: The average power loss of power devices over one grid cycle is calculated based on a pre-set converter main circuit model. The total thermal resistance of the power device from junction to environment is calculated based on a pre-set three-dimensional thermal network model of the power device. Initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device over one power grid cycle and the total thermal resistance of the power device from the junction to the environment; Based on the steady-state junction temperature, the electrical parameters are updated according to the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature. The converter main circuit model is updated based on the updated electrical parameters, and the closed-loop iteration continues until the electrothermal coupling converges, thus completing the modeling.

2. The modeling method for describing the electrothermal coupling characteristics of power devices and heat sinks according to claim 1, characterized in that, The converter main circuit model is constructed using PSpice software and includes a DC power supply, a three-phase inverter, and a three-phase filter connected in sequence. The three-phase inverter includes power devices.

3. The modeling method for describing the electrothermal coupling characteristics of power devices and heat sinks according to claim 1, characterized in that, The calculation of the average power loss of power devices within one grid cycle based on the pre-set converter main circuit model includes: Instantaneous current and voltage signals on power devices are obtained based on a pre-set converter main circuit model; The instantaneous power loss of the power device is calculated based on the instantaneous current and voltage signals; The average power loss of the power device over one power grid cycle is calculated based on the instantaneous power loss of the power device. : In the formula, For power devices at time Power loss, For the power grid cycle.

4. The modeling method for describing the electrothermal coupling characteristics of power devices and heat sinks according to claim 1, characterized in that, The steady-state junction temperature is: In the formula, For steady-state junction temperature and ambient temperature, This refers to the average power loss of a power device over one power grid cycle. The total thermal resistance from junction to environment; In the formula, The thermal resistance from junction to shell, This refers to the thermal resistance from the shell to the environment.

5. The modeling method for describing the electrothermal coupling characteristics of power devices and heat sinks according to claim 1, characterized in that, The three-dimensional thermal network model of the power device was constructed using Icepak software, including a junction-to-case thermal resistance model and a case-to-ambient thermal resistance model. Obtain the physical dimensions and thermal conductivity of the silicon chip and package of the power device, construct a junction-to-case thermal resistance model based on the law of thermal conduction, and calculate the junction-to-case thermal resistance. ; Obtain the thermal grease between the power device's package and the heatsink, the heatsink's physical dimensions and thermal conductivity, construct a thermal resistance model from the package to the environment based on the law of thermal conduction, and calculate the thermal resistance from the package to the environment. .

6. The modeling method for describing the electrothermal coupling characteristics of a power device-heat sink according to claim 5, characterized in that, The heat conduction law is based on Fourier's law: In the formula, The heat transfer flux is in the direction of heat conduction. Let be the cross-sectional area of ​​the heat-conducting medium perpendicular to the direction of heat conduction. The thermal conductivity of the heat-conducting medium. The distance in the direction of heat conduction. For temperature, The temperature gradient is along the direction of heat conduction. In the formula, These are the temperatures of the hot isotherm and the cold isotherm, respectively. The temperature difference between a thermal isotherm and a cold isotherm. The length of the heat conduction medium in the direction of heat conduction. This is the equivalent thermal resistance.

7. A modeling system for describing the electrothermal coupling characteristics of a power device-heat sink, characterized in that, include: The power consumption calculation module is configured to calculate the average power loss of power devices over a power grid cycle based on a pre-set converter main circuit model. The thermal resistance calculation module is configured to calculate the total thermal resistance of the power device from the junction to the environment based on a pre-set three-dimensional thermal network model of the power device. The junction temperature calculation module is configured to initialize the ambient temperature and calculate the steady-state junction temperature by combining the average power loss of the power device in one power grid cycle and the total thermal resistance of the power device from the junction to the environment. The parameter update module is configured to update the electrical parameters based on the steady-state junction temperature and according to the nonlinear characteristics of the temperature-related electrical parameters of the power device as a function of temperature. The iterative modeling module is configured to update the converter main circuit model based on the updated electrical parameters, and iterate in a closed loop until the electrothermal coupling converges, thus completing the modeling.

8. An electronic device, characterized in that, Including processor and storage media; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to perform the steps of the method according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-6.

10. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method described in any one of claims 1-6.

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