Method for detecting blocking state of forced air cooling heat dissipation system of power device under low air pressure

Abstract

According to the method for detecting the blocking state of the forced air cooling heat dissipation system of the power device under the low air pressure, simulation is carried out by establishing the finite element model of the forced air cooling heat dissipation system of the power device; a fluid thermal time constant is provided, and a mapping relation between the fluid thermal time constant and the blockage state and a model between the fluid thermal time constant and the temperature rise are established, so that other parameters of a forced heat dissipation system of the power device do not need to be identified; therefore, the detection efficiency can be effectively improved while the accuracy of the blockage state detection of the forced air cooling heat dissipation system is ensured, and accurate data support is provided for the operation of a power device.

Description

Technical Field

[0001] This invention relates to a method for detecting the status of power devices and related equipment, and more particularly to a method for detecting the blockage status of a forced air cooling system for power devices under low air pressure. Background Technology

[0002] Low-pressure regions typically possess abundant solar energy resources. Developing photovoltaic power generation in such regions is of great significance for ensuring energy security and promoting the construction of new power systems.

[0003] In photovoltaic power generation, numerous power devices are often involved. These devices require cooling during operation. Among existing technologies, forced air cooling technology is widely used in photovoltaic inverters due to its high heat dissipation efficiency and operational stability. However, during long-term operation, the combination of low air pressure and frequent strong winds can easily cause dust to accumulate in the radiator ducts, resulting in duct blockage. This blockage weakens the heat dissipation performance of the forced air cooling system, thereby shortening the service life of the power equipment.

[0004] Currently, the detection of blockage in forced air-cooled heat dissipation systems generally employs direct and indirect detection methods. Direct detection methods include temperature sensor threshold judgment and manual offline periodic inspections, which suffer from low monitoring efficiency and inaccurate results. Indirect detection methods assess the system's operating status by measuring parameters closely related to system performance and readily available. The effectiveness of this method depends on two key factors: (1) selecting characteristic quantities that accurately reflect the system's health status; and (2) establishing a reliable mapping relationship between these characteristic quantities and the system's operating status. However, existing indirect detection methods cannot meet these two conditions, thus failing to accurately determine the blockage status.

[0005] Therefore, in order to solve the above-mentioned technical problems, it is urgent to propose a new technical approach. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for detecting the blockage state of a forced air cooling system for power devices under low air pressure. By establishing a finite element model of the forced air cooling system for power devices for simulation, a fluid thermal time constant is proposed, and a mapping relationship between the fluid thermal time constant and the blockage state is established, as well as a model between the fluid thermal time constant and the temperature rise is established. Therefore, it is not necessary to identify other parameters of the forced air cooling system for power devices. Thus, while ensuring the accuracy of the blockage state detection of the forced air cooling system, the detection efficiency can be effectively improved, providing accurate data support for the operation of power devices.

[0007] This invention provides a method for detecting the blockage state of a forced air cooling system for power devices under low air pressure, comprising the following steps:

[0008] S1. Construct a finite element simulation model of the forced air cooling system for power devices, simulate the forced air cooling system under different blockage states, and obtain the operating parameters of the forced air cooling system under different blockage states.

[0009] S2. Construct a transient thermal model of the forced air cooling system and determine the virtual thermal time constant of the fluid;

[0010] S3. Establish a mapping table between the virtual thermal time constant of the fluid and the blockage state;

[0011] S4. Obtain the temperature parameters of the forced air cooling system of the power device in the actual working environment, and establish a model of transient temperature rise and fluid virtual thermal time constant;

[0012] S5. Solve the transient temperature rise and fluid virtual thermal time constant model to obtain the fluid virtual thermal time constant of the forced air cooling system of the power device in the actual working environment, and find the mapping relationship table in step S3 to determine the blockage state of the forced air cooling system in the actual working environment.

[0013] Furthermore, in step S2, constructing the transient thermal model of the forced air cooling system specifically includes:

[0014] ;

[0015] in: This represents the power loss due to fluid dissipation through the airflow duct of a forced air cooling system. This indicates the temperature rise of the fluid in the air duct of a forced air cooling system. and These represent the thermal resistance and virtual heat capacity of the fluid in the air duct, respectively. Represents the virtual thermal time constant of the fluid;

[0016] in: ; ;

[0017] Indicates the density of air. Q represents the specific heat capacity of air, Q represents the volumetric flow rate of the airflow through the radiator duct of the forced air cooling system, and V represents the equivalent volume of the fluid in the radiator duct.

[0018] Furthermore, establishing a model for transient temperature rise and the virtual thermal time constant of the fluid specifically includes:

[0019] ;

[0020] in: This represents the initial temperature rise of the fluid passing through the airflow path of the power device's heatsink. and These represent the outlet temperature and inlet temperature of the radiator, respectively.

[0021] Furthermore, by solving the transient temperature rise and fluid virtual thermal time constant model, the fluid virtual thermal time constant of the forced air cooling system for power devices in actual operating conditions is obtained, specifically including:

[0022] The transient temperature rise and fluid virtual thermal time constant model is rewritten as follows:

[0023] ;

[0024] Establish the objective function for the transient temperature rise fitting process:

[0025] ;

[0026] in: and These represent the calculated temperature value and the measured temperature value, respectively. M represents the number of measurement data points, and x represents the virtual thermal time constant of the fluid.

[0027] The virtual thermal time constant of the fluid is calculated iteratively according to the following equation:

[0028] ;

[0029] in Indicates the number of iterations. This indicates the amount of parameter value update in each iteration;

[0030] Parameter value update amount Determined by the following equation:

[0031] ;

[0032] Where: J represents the sensitivity coefficient matrix, and diag() represents the diagonal elements of the sensitivity coefficient matrix. Indicates the damping coefficient;

[0033] The sensitivity coefficient matrix is ​​as follows:

[0034] ;

[0035] The calculated value for fluid temperature rise is as follows:

[0036] ;

[0037] when When the time limit is reached, the iterative calculation is stopped, and the final virtual thermal time constant of the fluid is obtained. To set the coefficients.

[0038] The beneficial effects of this invention are as follows: By establishing a finite element model of the forced air cooling system of power devices for simulation, a fluid thermal time constant is proposed, and a mapping relationship between the fluid thermal time constant and the blockage state is established, as well as a model between the fluid thermal time constant and the temperature rise is established. Therefore, it is not necessary to identify other parameters of the forced cooling system of power devices. Thus, while ensuring the accuracy of the blockage state detection of the forced air cooling system, the detection efficiency can be effectively improved, providing accurate data support for the operation of power devices. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0040] Figure 1 This is a schematic diagram of the process of the present invention.

[0041] Figure 2 This is a schematic diagram of a forced air cooling system for power devices.

[0042] Figure 3 This is a schematic diagram illustrating the relationship between the transient temperature rise of the fluid and the virtual thermal time constant of the extraction in this invention. Detailed Implementation

[0043] The present invention will be further described in detail below:

[0044] This invention provides a method for detecting the blockage state of a forced air cooling system for power devices under low air pressure, comprising the following steps:

[0045] S1. Construct a finite element simulation model of the forced air cooling system for power devices, simulate the forced air cooling system under different blockage states, and obtain the operating parameters of the forced air cooling system under different blockage states; the finite element simulation model is built using existing simulation software, and in the simulation model, it is necessary to set the air pressure in the simulation to be the same as the air pressure of the power device to be evaluated.

[0046] S2. Construct a transient thermal model of the forced air cooling system and determine the virtual thermal time constant of the fluid;

[0047] S3. Establish a mapping table between the virtual thermal time constant of the fluid and the blockage state;

[0048] S4. Obtain the temperature parameters of the forced air cooling system of the power device in the actual working environment, and establish a model of transient temperature rise and fluid virtual thermal time constant; wherein, the forced air cooling system of the power device in the actual working environment is the target to be evaluated.

[0049] S5. Solve the transient temperature rise and fluid virtual thermal time constant model to obtain the fluid virtual thermal time constant of the forced air cooling system of the power device in the actual operating environment, and determine the blockage state of the forced air cooling system in the actual operating environment by looking up the mapping relationship table in step S3. Through this invention, by establishing a finite element model of the forced air cooling system of the power device for simulation, the fluid thermal time constant is proposed and a mapping relationship between the fluid thermal time constant and the blockage state is established, as well as a model between the fluid thermal time constant and the temperature rise is established. Therefore, it is not necessary to identify other parameters of the forced cooling system of the power device. Thus, while ensuring the accuracy of the blockage state detection of the forced air cooling system, it can effectively improve the detection efficiency and provide accurate data support for the operation of the power device.

[0050] The structural schematic diagram of the forced air cooling system for power devices is shown below. Figure 2 As shown, the fluid in this embodiment refers to air in a low-pressure environment.

[0051] In this embodiment, step S2, constructing the transient thermal model of the forced air cooling system specifically includes:

[0052] ;

[0053] in: This represents the power loss due to fluid dissipation through the airflow duct of a forced air cooling system. This indicates the temperature rise of the fluid in the air duct of a forced air cooling system. and These represent the thermal resistance and virtual heat capacity of the fluid in the air duct, respectively. Represents the virtual thermal time constant of the fluid;

[0054] in: ; ;

[0055] Indicates the density of air. Let Q represent the specific heat capacity of air, Q represent the volumetric flow rate of the fluid flowing through the radiator duct of the forced air cooling system, and V represent the equivalent volume of the fluid in the radiator duct. Through the above process, the fluid thermal time constant can be obtained and can be correlated with different blockage states in the simulation. and as well as Parameters can be obtained from simulation models; however, under actual working conditions, these parameters are either unavailable or difficult to obtain, and their accuracy is hard to guarantee. Therefore, the following process is needed to avoid measuring these parameters. Specifically:

[0056] Establishing a model for transient temperature rise and the virtual thermal time constant of the fluid specifically includes:

[0057] ;

[0058] in: This represents the initial temperature rise of the fluid passing through the airflow path of the power device's heatsink. and These represent the outlet temperature and inlet temperature of the radiator, respectively.

[0059] Solving the transient temperature rise and fluid virtual thermal time constant model yields the fluid virtual thermal time constant of the forced air cooling system for power devices in actual operating conditions. Specifically, this includes:

[0060] The transient temperature rise and fluid virtual thermal time constant model is rewritten as follows:

[0061] Therefore, in this model, it is only necessary to determine And the coefficient A is sufficient, and Since the inlet and outlet temperatures of the radiator duct are obtained through sensors, then only coefficient A needs to be determined, specifically:

[0062] Establish the objective function for the transient temperature rise fitting process:

[0063] ;

[0064] in: and These represent the calculated temperature value and the measured temperature value, respectively. M represents the number of measurement data points, and x represents the virtual thermal time constant of the fluid.

[0065] The virtual thermal time constant of the fluid is calculated iteratively according to the following equation:

[0066] ;

[0067] in Indicates the number of iterations. This indicates the amount of parameter value update in each iteration;

[0068] Parameter value update amount Determined by the following equation:

[0069] ;

[0070] Where: J represents the sensitivity coefficient matrix, and diag() represents the diagonal elements of the sensitivity coefficient matrix. Indicates the damping coefficient;

[0071] The sensitivity coefficient matrix is ​​as follows:

[0072] ;

[0073] The calculated value for fluid temperature rise is as follows:

[0074] ;

[0075] when When the time limit is reached, the iterative calculation is stopped, and the final virtual thermal time constant of the fluid is obtained. To set the coefficients, the coefficient A can be obtained through the above process using existing fitting methods. Then, it can be substituted into the transient temperature rise and fluid virtual thermal time constant model. At this time, the fluid thermal time constant in the actual working environment can be calculated by using the real-time measured inlet and outlet temperatures and the acquisition time t. Then, by looking up the corresponding relationship table, the current blockage state can be obtained.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for detecting blockage in a forced air cooling system for power devices under low air pressure, characterized in that: Includes the following steps: S1. Construct a finite element simulation model of the forced air cooling system for power devices, simulate the forced air cooling system under different blockage states, and obtain the operating parameters of the forced air cooling system under different blockage states. S2. Construct a transient thermal model of the forced air cooling system and determine the virtual thermal time constant of the fluid; S3. Establish a mapping table between the virtual thermal time constant of the fluid and the blockage state; S4. Obtain the temperature parameters of the forced air cooling system of the power device in the actual working environment, and establish a model of transient temperature rise and fluid virtual thermal time constant; S5. Solve the transient temperature rise and fluid virtual thermal time constant model to obtain the fluid virtual thermal time constant of the forced air cooling system of the power device in the actual working environment, and find the mapping relationship table in step S3 to determine the blockage state of the forced air cooling system in the actual working environment.

2. The method for detecting blockage in a forced air-cooled heat dissipation system for power devices under low air pressure according to claim 1, characterized in that: In step S2, constructing the transient thermal model of the forced air cooling system specifically includes: ； in: This represents the power loss due to fluid dissipation through the airflow duct of a forced air cooling system. This indicates the temperature rise of the fluid in the air duct of a forced air cooling system. and These represent the thermal resistance and virtual heat capacity of the fluid in the air duct, respectively. Represents the virtual thermal time constant of the fluid; in: ; ; Indicates the density of air. Q represents the specific heat capacity of air, Q represents the volumetric flow rate of the airflow through the radiator duct of the forced air cooling system, and V represents the equivalent volume of the fluid in the radiator duct.

3. The method for detecting blockage in a forced air-cooled heat dissipation system for power devices under low air pressure according to claim 2, characterized in that: Establishing a model for transient temperature rise and the virtual thermal time constant of the fluid specifically includes: ； in: This represents the initial temperature rise of the fluid passing through the airflow path of the power device's heatsink. and These represent the outlet temperature and inlet temperature of the radiator, respectively.

4. The method for detecting blockage in a forced air-cooled heat dissipation system for power devices under low air pressure according to claim 3, characterized in that: Solving the transient temperature rise and fluid virtual thermal time constant model yields the fluid virtual thermal time constant of the forced air cooling system for power devices in actual operating conditions. Specifically, this includes: The transient temperature rise and fluid virtual thermal time constant model is rewritten as follows: ； Establish the objective function for the transient temperature rise fitting process: ； in: and These represent the calculated temperature value and the measured temperature value, respectively. M represents the number of measurement data points, and x represents the virtual thermal time constant of the fluid. The virtual thermal time constant of the fluid is calculated iteratively according to the following equation: ； in Indicates the number of iterations. This indicates the amount of parameter value update in each iteration; Parameter value update amount Determined by the following equation: ； Where: J represents the sensitivity coefficient matrix, and diag() represents the diagonal elements of the sensitivity coefficient matrix. Indicates the damping coefficient; The sensitivity coefficient matrix is ​​as follows: ； The calculated value for fluid temperature rise is as follows: ； when When the time limit is reached, the iterative calculation is stopped, and the final virtual thermal time constant of the fluid is obtained. To set the coefficients.

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