Method for judging blockage degree of air outlet of air-cooled power supply system

Abstract

The invention provides a method for judging the blockage degree of an air outlet of an air-cooled power supply system, and belongs to the field of thermal simulation computation.In a simulation system, the boundary condition of the air-cooled power supply system is set, the ventilation rate is set to be 0.1, the module temperature T1 and the outlet air temperature T2 are obtained through calculation based on fluid dynamics, and the module allowable temperature Tx is set; according to an empirical formula, the alarm temperature T2'of the air outlet is obtained through calculation, the empirical formula is T2 '= T2 + a delta T, delta T represents the difference value between the module allowable temperature Tx and the module temperature T1, delta T = Tx-T1, a represents the set allowance, and a belongs to [1 / 5, 1 / 2]; the ventilation rate is sequentially and gradually increased from 0.1 to 1 according to a set threshold value for thermal simulation calculation, and a relation curve of the alarm temperature T2'of the air outlet and the ventilation rate is obtained through fitting; based on the relation curve of the air outlet alarm temperature T2'and the ventilation rate, the air outlet blocking degree of the air cooling power supply system is judged, and the system blocking condition can be accurately and rapidly judged.

Description

Technical Field

[0001] The invention relates to the technical field of thermal simulation calculation, and in particular to a method for judging the blockage degree of an air outlet of an air-cooled power supply system. Background Art

[0002] For air-cooled power supply systems, temperature monitoring points are often set on the heat sink substrate to monitor the temperature of the modules on the heat sink. Generally, through actual product testing, it is found that the temperature of the monitoring point is too high, and then a system analysis is performed to find the cause of the excessive temperature. Usually, the monitoring temperature alarm value is a fixed value, and the relationship between the system ventilation condition and the module temperature is not designed. It is impossible to give the blockage condition of the system air inlet and outlet through real-time temperature detection.

[0003] The paper "Research on Heat Dissipation Performance of Nuclear-Grade DCS Chassis Equipment and Analysis of Influencing Factors" (Li Huaqiao et al., Xi'an Jiaotong University, School of Energy and Power Engineering, etc., Journal of Chongqing University of Technology (Natural Science), 2023) shows that the ventilation rate and chip temperature are negatively correlated. The temperature of the chip has many influencing factors, which may be poor contact of the interface material, poor soldering of the pad, abnormal current, etc. The paper focuses on the chip temperature, and there are many reasons for the overheating of the radiator in the air-cooled power supply system. Since the paper did not pay attention to the outlet temperature, it was unable to determine that the overheating of the radiator was caused by the blockage of the outlet. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to accurately and quickly determine the blockage degree of the air outlet of an air-cooled power supply system.

[0005] The present invention solves the above technical problems through the following technical solutions: a method for judging the blockage degree of the air outlet of an air-cooled power supply system, comprising the following steps:

[0006] Step 1: Set the boundary conditions of the air-cooled power system in the simulation system, including ambient temperature T0, heat consumption Q, material properties, fan characteristics, three-dimensional physical models of each component, and initial ambient pressure;

[0007] Step 2: Set the ventilation rate to 0.1, calculate the module temperature T1 and outlet air temperature T2 based on fluid dynamics, and set the module allowable temperature T x , the outlet alarm temperature T2′ is calculated according to the empirical formula, the empirical formula is:

[0008] T2′=T2+aΔT

[0009] Where ΔT represents the module allowable temperature T x The difference between the module temperature T1, ΔT = T x -T1, a represents the set margin, a∈[1 / 5,1 / 2];

[0010] Step 3: Perform thermal simulation calculations by increasing the ventilation rate from 0.1 to 1 according to the set threshold, and obtain a curve of the relationship between the air outlet alarm temperature T2′ and the ventilation rate by fitting;

[0011] Step 4: Based on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate, determine the blockage degree of the air outlet of the air-cooled power system.

[0012] Preferably, the step 2 of obtaining the module temperature T1 and the outlet air temperature T2 based on computational fluid dynamics calculations includes:

[0013] The boundary conditions of the air-cooled power supply system are input into the simulation software, and the simulation model grid is divided into multiple small grids. The mass conservation equation, momentum conservation equation, and energy conservation equation of all small grids are obtained based on fluid dynamics. The temperature, pressure, and velocity at all positions in the simulation model are calculated, and then the module temperature T1 and the outlet air temperature T2 are obtained.

[0014] Preferably, the step three comprises:

[0015] Determine whether the ventilation rate value is less than 1. If so, add the ventilation rate value to the set threshold, return to step 2 to recalculate the outlet alarm temperature T2′ until the ventilation rate value is equal to 1, end the calculation, and output the ventilation rate, module temperature T1, and outlet alarm temperature T2′.

[0016] Preferably, the step 4 comprises:

[0017] Temperature sensors are installed at the air outlet and power module of the air-cooled power system respectively to read the module temperature and air temperature of the air outlet of the air-cooled power system. The air outlet alarm temperature T2′ is calculated according to the empirical formula. The corresponding ventilation rate η is found on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate. The degree of blockage of the air outlet is judged according to the ventilation rate η.

[0018] Preferably, the set margin a is set to a value of 1 / 3.

[0019] Preferably, the threshold value range is set in step three to be 0.05-0.2.

[0020] Preferably, the air-cooled power supply system includes a power module, a control module, a radiator and a fan. The power module, the control module and the radiator are all located in a power supply box. The power supply box has an air inlet at one end and an air outlet at the other end. The fan is located at the air outlet.

[0021] The advantages of the present invention are:

[0022] The present invention performs thermal simulation calculation on the ventilation rate of the air-cooled power system from 10% to 100%, obtains the relationship (relationship curve) between the air outlet alarm temperature and the ventilation rate in the product design stage, and uses the allowable temperature T x The difference between the module temperature T1 is used to set the sum of the margin and the outlet temperature as the alarm protection value. The outlet alarm temperature fed back by the system operation is used to find the corresponding ventilation rate value on the relationship curve. Since the outlet temperature and the ventilation rate respond almost directly, the system blockage situation can be accurately and quickly judged. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of an air-cooled power supply system provided for an embodiment of the present invention;

[0024] Figure 2 A flow chart of a method for determining the degree of blockage of an air outlet of an air-cooled power supply system provided by an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of momentum conservation of a single small grid in a method for determining the blockage degree of an air outlet of an air-cooled power supply system provided by an embodiment of the present invention;

[0026] Figure 4 A curve diagram showing the relationship between the air outlet alarm temperature and the ventilation rate in the method for determining the degree of blockage of the air outlet of an air-cooled power supply system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the technical solution of the present invention is clearly and completely described below in combination with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, this embodiment provides a method for judging the degree of blockage of the air outlet of an air-cooled power supply system, which can calculate the relationship curve between the air outlet alarm temperature and the ventilation rate in the product design stage, and can judge the blockage of the air outlet of the air-cooled power supply system according to the relationship curve. The air-cooled power supply system includes a power module 20, a control module, a radiator 30 and a fan 40, the power module 20, the control module, and the radiator 30 are all located in a power supply box 10, one end of the power supply box 10 has an air inlet, and the other end has an air outlet, and the fan 40 is located at the air outlet.

[0029] like Figure 2 As shown, the judging method comprises the following steps:

[0030] Step 1: Set the boundary conditions of the air-cooled power system in the simulation system, including ambient temperature T0, heat loss Q, material properties, fan characteristics, three-dimensional physical models of each component, and initial ambient pressure.

[0031] Step 2: Set the ventilation rate to 0.1, calculate the module temperature T1 and outlet air temperature T2 based on computational fluid dynamics, and set the module allowable temperature T x , the outlet alarm temperature T2′ is calculated according to the empirical formula, the empirical formula is:

[0032] T2′=T2+aΔT

[0033] Where ΔT represents the module allowable temperature T x The difference between the module temperature T1, ΔT = T x -T1, a represents the set margin, a∈[1 / 5,1 / 2].

[0034] The present invention sets the value of the margin a to be 1 / 3.

[0035] The module temperature T1 and the outlet temperature T2 are calculated based on the specific power box boundary input through simulation software based on computational fluid dynamics (CFD) (such as icepak).

[0036] like Figure 3 As shown, the basic differential equations of computational fluid dynamics (CFD) are composed of the mass conservation equation (continuity equation) as shown in formula (1), the momentum conservation equation (three equations in the X, Y, and Z directions) as shown in formulas (2)-(4), and the energy conservation equation as shown in formula (5). The five equations and five unknowns can obtain a convergent solution, and the five parameters obtained are: temperature, pressure, speed in the X direction, speed in the Y direction, and speed in the Z direction.

[0037]

[0038]

[0039] The model to be solved is meshed and divided into a sufficient number of small grids (such as 1 million). The above five equations are calculated simultaneously for all small grids to obtain the temperature, pressure and velocity at all positions in the entire model, and then the values ​​of the module temperature T1 and the outlet temperature T2 can be read.

[0040] Step 3: Perform thermal simulation calculations by increasing the ventilation rate from 0.1 to 1 according to the set threshold, and obtain a curve of the relationship between the air outlet alarm temperature T2′ and the ventilation rate by fitting.

[0041] Determine whether the ventilation rate value is less than 1. If so, add the ventilation rate value to the set threshold value, return to step 2 to recalculate the outlet alarm temperature T2' until the ventilation rate value is equal to 1, end the calculation, and output the ventilation rate, module temperature T1, and outlet alarm temperature T2'. The threshold value range is set to 0.05-0.2. The smaller the value of the set threshold value, the more accurate the calculation result. The set threshold value of the present invention is taken as 0.1.

[0042] Step 4: Based on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate, determine the blockage degree of the air outlet of the air-cooled power system.

[0043] Temperature sensors are installed at the air outlet and power module of the air-cooled power system respectively to detect and read the module temperature and air outlet temperature of the air-cooled power system in real time. The air outlet alarm temperature T2′ is calculated according to the empirical formula, and the corresponding ventilation rate η is found on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate. The degree of blockage of the air outlet is judged according to the ventilation rate η.

[0044] Working principle:

[0045] For air-cooled systems, when the air inlet and outlet of the system are blocked or unblocked, the temperature change of the power module is usually greater than the temperature change of the outlet. If the outlet temperature is used as the alarm temperature, it may not be possible to accurately protect the module operation. The present invention performs thermal simulation calculations on the ventilation rate of the air-cooled power system from 10% to 100%, and obtains the relationship (relationship curve) between the outlet alarm temperature and the ventilation rate during the product design stage, such as Figure 4 As shown, the allowable temperature T x The difference between the module temperature T1 is used to set the sum of the margin △T / 3 and the outlet temperature as the alarm protection value. The outlet alarm temperature fed back by the system operation is used to find the corresponding ventilation rate value on the relationship curve. Since the outlet temperature and the ventilation rate respond almost directly, the system blockage situation can be directly judged, and the user can be notified in time to clean the inlet and outlet to extend the service life.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the blockage degree of an air outlet of an air-cooled power supply system, characterized in that: The following steps are involved: Step 1: Set the boundary conditions of the air-cooled power system in the simulation system, including ambient temperature T0, heat consumption Q, material properties, fan characteristics, three-dimensional physical models of each component, and initial ambient pressure; Step 2: Set the ventilation rate to 0.1, calculate the module temperature T1 and outlet air temperature T2 based on fluid dynamics, and set the module allowable temperature T x , the outlet alarm temperature T2′ is calculated according to the empirical formula, the empirical formula is: T2′=T2+aΔT Where ΔT represents the module allowable temperature T x The difference between the module temperature T1, ΔT = T x -T1, a represents the set margin, a∈[1 / 5,1 / 2]; Step 3: Perform thermal simulation calculations by increasing the ventilation rate from 0.1 to 1 according to the set threshold, and obtain a curve of the relationship between the air outlet alarm temperature T2′ and the ventilation rate by fitting; Step 4: Based on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate, determine the blockage degree of the air outlet of the air-cooled power system.

2. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: The module temperature T1 and the outlet air temperature T2 are calculated based on computational fluid dynamics in step 2, including: The boundary conditions of the air-cooled power supply system are input into the simulation software, and the simulation model grid is divided into multiple small grids. The mass conservation equation, momentum conservation equation, and energy conservation equation of all small grids are obtained based on fluid dynamics. The temperature, pressure, and velocity at all positions in the simulation model are calculated, and then the module temperature T1 and the outlet air temperature T2 are obtained.

3. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: The step three comprises: Determine whether the ventilation rate value is less than 1. If so, add the ventilation rate value to the set threshold, return to step 2 to recalculate the outlet alarm temperature T2′ until the ventilation rate value is equal to 1, end the calculation, and output the ventilation rate, module temperature T1, and outlet alarm temperature T2′.

4. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: The fourth step comprises: Temperature sensors are installed at the air outlet and power module of the air-cooled power system respectively to read the module temperature and air temperature of the air outlet of the air-cooled power system. The air outlet alarm temperature T2′ is calculated according to the empirical formula. The corresponding ventilation rate η is found on the relationship curve between the air outlet alarm temperature T2′ and the ventilation rate. The degree of blockage of the air outlet is judged according to the ventilation rate η.

5. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: The set margin a is set to a value of 1 / 3.

6. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: In the step three, the threshold range is set to 0.05-0.

2.

7. The method for judging the blockage degree of the air outlet of the air-cooled power supply system according to claim 1, characterized in that: The air-cooled power supply system includes a power module, a control module, a radiator and a fan. The power module, the control module and the radiator are all located in a power supply box. The power supply box has an air inlet at one end and an air outlet at the other end. The fan is located at the air outlet.

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