IGBT module service life prediction method and detection device
By combining high-precision and low-precision calculation models, a linear relationship between junction temperature change and power loss is constructed. Combined with the Coffin-Manson lifetime model, the problem of inaccurate IGBT module lifetime prediction is solved, achieving more accurate lifetime prediction and ensuring equipment safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HITACHI LTD
- Filing Date
- 2024-11-08
- Publication Date
- 2026-05-08
AI Technical Summary
In existing technologies, the lifespan prediction of IGBT modules is not accurate enough, especially under the influence of power cycling caused by frequent heating and cooling processes. The inability to accurately predict their lifespan may lead to equipment downtime or accidents.
By combining a high-precision first calculation model with a low-precision second calculation model, and by constructing a linear relationship between junction temperature change and power loss, and combining it with the Coffin-Manson lifetime model, the junction temperature change of the IGBT module is accurately calculated, avoiding calculation errors caused by inconsistent or long time intervals.
This improves the accuracy of IGBT module lifespan prediction, avoids prediction errors caused by inconsistent or excessive time intervals, and ensures the normal use and safety of IGBT modules.
Smart Images
Figure CN121995185A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of data detection, and in particular to a method and device for predicting the lifespan of an IGBT module. Background Technology
[0002] Currently, Insulated-Gate Bipolar Transistor (IGBT) modules are widely used in the railway industry. During operation, IGBT modules are constantly heated and cooled, resulting in frequent power cycles. Over time, these cycles accumulate and eventually affect the lifespan of the IGBT modules, potentially causing equipment downtime or even more serious accidents. For example, an unused IGBT module might have a lifespan of 15 years, but with continuous heating and cooling during use, its lifespan could be shortened to 10 years. Failure to effectively monitor the IGBT module's lifespan can easily lead to accidents. Therefore, it is necessary to predict the lifespan of IGBT modules to avoid accidents caused by their end. Summary of the Invention
[0003] This application provides an IGBT module life prediction method and detection device to solve the problem of inaccurate IGBT module life prediction.
[0004] In a first aspect, this application provides an IGBT module lifetime prediction method applied to a testing device. The testing device includes a first calculation model, a second calculation model, and a first lifetime prediction model. The method includes: determining a first junction temperature change value corresponding to a first time interval of the IGBT module using the first calculation model; if the first junction temperature change value is greater than or equal to a preset first junction temperature threshold, determining a second junction temperature change value corresponding to the first time interval of the IGBT module using the second calculation model; if the second junction temperature change value is greater than or equal to the first junction temperature threshold, obtaining a plurality of third junction temperature change values corresponding to multiple second time intervals and a plurality of power losses corresponding to multiple second time intervals, wherein the third junction temperature change values are calculated before the first junction temperature change values and are less than the first junction temperature threshold; constructing a first linear relationship based on the plurality of power losses and the plurality of third junction temperature change values; determining a fourth junction temperature change value corresponding to the first time interval based on the first linear relationship and the power losses corresponding to the first time interval, wherein the fourth junction temperature change value is less than the first junction temperature threshold; and inputting the fourth junction temperature change value into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module.
[0005] In one possible implementation of the first aspect above, the method further includes: if the first junction temperature change value is less than the first junction temperature threshold, inputting the first junction temperature change value into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module; or, if the second junction temperature change value is less than the first junction temperature threshold, inputting the second junction temperature change value into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module.
[0006] In one possible implementation of the first aspect described above, the preset first junction temperature threshold includes 125°C.
[0007] In one possible implementation of the first aspect above, the method further includes: obtaining the specification parameters of the IGBT module, including resistance and thermal impedance; determining the power loss of the IGBT module in the first time interval based on the current of the IGBT module in the first time interval; and constructing a first calculation model or a second calculation model based on the specification parameters, the power loss and the first time interval.
[0008] In one possible implementation of the first aspect described above, the first calculation model determines the first junction temperature change value using the following formula:
[0009]
[0010] Where, ΔT j -1 represents the first junction temperature change, Δt represents the first time interval, i = 1, 2, 3, 4, representing the number of resistors included in the IGBT module, and τ th,i P represents the thermal impedance corresponding to the i-th resistor in the IGBT module. i This represents the power loss of the i-th resistor in the first time interval Δt of the IGBT module. j,i (j-1) represents the junction temperature change value of the i resistors of the IGBT module corresponding to the time interval before the first time interval.
[0011] In one possible implementation of the first aspect described above, the second calculation model determines the second junction temperature change value using the following formula:
[0012]
[0013] Where, ΔT j -2 represents the second junction temperature change value, R represents the resistance value corresponding to the IGBT module, Δt represents the first time interval, and τ th P represents the thermal impedance of the IGBT module, and P represents the power loss of the IGBT module in the first time interval Δt. j,i (j-1) represents the junction temperature change value of the IGBT module corresponding to the time interval preceding the first time interval.
[0014] In one possible implementation of the first aspect described above, a first time moment and a second time moment are randomly collected, and the first time interval is determined by the time interval between the first time moment and the second time moment.
[0015] In one possible implementation of the first aspect described above, the interval duration of the first time interval and the interval duration of the second time interval are both less than a preset first duration threshold.
[0016] In one possible implementation of the first aspect above, the first linear relationship includes: the third junction temperature change value is proportional to the power loss corresponding to the plurality of second time intervals.
[0017] Secondly, embodiments of this application provide a detection device, which includes:
[0018] The first calculation model is used to determine the first junction temperature change value of the IGBT module corresponding to the first time interval.
[0019] The second calculation model is used to determine the second junction temperature change value of the IGBT module corresponding to the first time interval when the first junction temperature change value is greater than or equal to the preset first junction temperature threshold. The first lifetime prediction model is used to determine the target predicted lifetime of the corresponding IGBT module based on the fourth junction temperature change value when the second junction temperature change value is greater than or equal to the first junction temperature threshold. The fourth junction temperature change value is less than the first junction temperature threshold. The fourth junction temperature change value is determined based on the first linear relationship and the power loss corresponding to the first time interval. The first linear relationship is determined based on the third junction temperature change value corresponding to multiple second time intervals and the power loss corresponding to multiple second time intervals. The third junction temperature change value is calculated before the first junction temperature change value and is less than the first junction temperature threshold.
[0020] The beneficial effects of this application embodiment are: when the historical time interval of multiple IGBT module junction temperature acquisitions is long or the historical time intervals are different, the junction temperature change value of the IGBT module can be calculated more accurately through the above scheme, thereby predicting the life of the IGBT module. Attached Figure Description
[0021] Figure 1 According to some embodiments of this application, a coordinate graph showing the relationship between time intervals and junction temperature changes of an IGBT module is shown.
[0022] Figure 2 According to some embodiments of this application, a schematic flowchart of an IGBT module lifetime prediction method is shown;
[0023] Figure 3 According to some embodiments of this application, a coordinate graph showing the relationship between time intervals and junction temperature changes of an IGBT module is shown.
[0024] Figure 4 A schematic diagram of a detection device is shown according to some embodiments of this application. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.
[0026] The following is an explanation of the terms mentioned in the embodiments of this application:
[0027] The junction temperature of an IGBT module can be expressed as the actual temperature of the IGBT module under operating conditions. For example, the junction temperature of an IGBT module is related to parameters such as power loss and thermal impedance.
[0028] Junction temperature change calculation model: Two random time points are collected, and based on the power loss, thermal impedance, and other parameters of the IGBT module corresponding to the two randomly collected time points, the junction temperature change value (ΔT) of the IGBT module within the time interval corresponding to the two randomly collected time points is calculated. j (The specific calculation process is described below and will not be repeated here.) For example, in the railway industry, the ΔT of the IGBT module... j The maximum value is 125℃, which means that the maximum difference in junction temperature of the IGBT module between adjacent time points (minimum time interval) is 125℃. In other words, when the junction temperature change calculated by the junction temperature change calculation model is less than 125℃, it is a normal situation; while when the junction temperature change calculated by the junction temperature change calculation model is greater than or equal to 125℃, it is an abnormal situation.
[0029] In some embodiments, the impact of the junction temperature change calculation model on the junction temperature change value of the IGBT module is gradually accumulated. For example, if the current junction temperature change value calculated by the junction temperature change calculation model at the current time interval is greater than or equal to 125°C, it is usually because the historical time interval for calculating a certain historical junction temperature change value is long, or because the historical time intervals corresponding to multiple historical junction temperature change values are different; that is, the influence of the historical time interval leads to an abnormal situation in the current junction temperature change value calculated at the current time interval.
[0030] Coffin-Manson lifetime model: based on the junction temperature change (ΔT) of the IGBT module. j The lifespan of IGBT modules is predicted (the specific prediction process is described below and will not be repeated here).
[0031] Understandably, to address the aforementioned issues, some solutions can use a junction temperature change calculation model to determine the junction temperature change value (ΔT) of the IGBT module. j The lifespan of the IGBT module is then predicted using the Coffin-Manson lifetime model (corresponding to the first lifetime prediction model mentioned above).
[0032] However, as mentioned earlier, the influence of historical time intervals may cause anomalies in the current junction temperature change values calculated for the current time interval. For example, Figure 1 The time interval shown is related to the junction temperature change (ΔT) of the IGBT module. j The graph shows the relationship between the IGBT module and its junction temperature. The horizontal axis represents the time interval (s), and the vertical axis represents the junction temperature change of the IGBT module (ΔT). j The range is 0 to 250℃; this corresponds to a situation where there are multiple different historical time intervals within time period T1 (or time period T2) and the historical time intervals are relatively long; because the influence of the junction temperature change calculation model on the IGBT module's junction temperature change value gradually accumulates, the junction temperature change calculation model calculates ΔT... j In cases where the temperature is ≥125℃, such as Figure 1 The junction temperature change value pointed to by 101.
[0033] Obviously, for the abnormal case ΔT j If the Coffin-Manson lifetime model is used to predict the IGBT module's lifetime under these circumstances, it may lead to prediction errors. For example, an unused IGBT module might have a lifetime of 15 years. After two years of use, its lifetime could be 10 to 13 years. However, using the method described above to predict the IGBT module's lifetime, the prediction might not be accurate in ΔT. j Predicting the remaining lifespan of an IGBT module to be 1 year at ≥125℃ is far from the actual unused lifespan of the IGBT module and cannot be used as a reference. Therefore, this method is unsuitable for predicting IGBT module lifespan and also affects the normal use of the IGBT module.
[0034] To address the aforementioned issues, this application provides a method for predicting the lifetime of an IGBT module. In this method, for an IGBT module whose lifetime is to be predicted, a first junction temperature change value within a first time interval is determined using a first calculation model with higher accuracy and stricter time interval requirements. If the first junction temperature change value is less than a first junction temperature threshold (e.g., ΔT), the prediction is further supported by the method. jIf the IGBT module's lifespan is <125℃, then the lifespan is predicted based on the first junction temperature change value and the Coffin-Manson lifetime model. If the first junction temperature change value is greater than or equal to the first junction temperature threshold, it indicates that the first calculation model's calculation of the first junction temperature change value for the first time interval is abnormal due to the influence of historical time intervals. Therefore, it is necessary to further recalculate the junction temperature change value of the IGBT module in the first time interval using a second calculation model with lower time interval requirements. If the second junction temperature change value calculated by the second calculation model is less than the first junction temperature threshold, then the lifespan of the IGBT module is predicted based on the second junction temperature change value and the Coffin-Manson lifetime model. If the second junction temperature change value is greater than or equal to the first junction temperature threshold, then multiple historical junction temperature change values less than the first junction temperature threshold are obtained from the historical time intervals of the calculated historical junction temperature change values as the third junction temperature change value, along with the power loss of the historical time intervals corresponding to the multiple third junction temperature change values (examples of the second time interval, hereinafter referred to as the second time interval). By constructing a first linear relationship between the power loss P of the IGBT module in the second time interval when it is less than the first junction temperature threshold and the third junction temperature change value, the fourth junction temperature change value of the IGBT module in the first time interval is determined based on the first linear relationship. Then, the lifetime of the IGBT module is predicted based on the fourth junction temperature change value and the Coffin-Manson lifetime model.
[0035] The interval length of the first time interval and the interval length of the second time interval are both less than the first duration threshold.
[0036] In some optional instances, the first computational model can be represented as: Furthermore, the first calculation model features high computational accuracy and strict requirements on time intervals. The second calculation model can be expressed as: Furthermore, the second calculation model has the characteristics of lower time interval requirements and lower calculation accuracy. Therefore, if the first calculation model calculates that the IGBT model is greater than or equal to the first junction temperature threshold, it indicates that the time interval for collecting the junction temperature of the IGBT module is long or the time interval is not fixed. Thus, the second calculation model can recalculate, which can better make up for the problem of the first calculation model's high time interval requirements and calculation errors.
[0037] In some optional instances, the Coffin-Manson lifetime model can be expressed as: Where α, n, E α , k and T m All are Coffin-Manson lifetime model coefficients; ΔT j N represents the junction temperature change value of the IGBT module. f This is the predicted lifespan of the IGBT module.
[0038] Thus, when there are long or inconsistent historical time intervals between multiple IGBT module junction temperature measurements, resulting in a first junction temperature change value greater than or equal to a first junction temperature threshold in the first time interval, the first calculation model, which has a higher time interval requirement, firstly determines that the first junction temperature change value is greater than or equal to the first junction temperature threshold. Then, the second calculation model, which has a lower time interval requirement, determines the second junction temperature change value. Finally, by constructing a first linear relationship between the power loss P of the IGBT module in the second time interval when the junction temperature is below the first junction temperature threshold and the third junction temperature change value, the fourth junction temperature change value is determined. This avoids the situation where the calculation of the first junction temperature change value of the IGBT module in the first time interval is incorrect due to long or inconsistent time intervals for junction temperature measurement, thus affecting the inaccurate prediction of the IGBT module's lifespan.
[0039] The IGBT module lifespan prediction method provided in this application can accurately calculate the junction temperature change value of the IGBT module and predict its lifespan when the historical time intervals for multiple collections of IGBT module junction temperature are long or the historical time intervals are different.
[0040] In some instances, an IGBT module may include multiple resistors. The junction temperature change of the IGBT module during a first time interval is obtained, which corresponds to obtaining the sum of the junction temperature changes of the multiple resistors in the IGBT module. For example, an IGBT module may include 4 resistors, 5 resistors, etc. For ease of description, this application will use an IGBT module including 4 resistors and a first junction temperature threshold of 125°C as an example.
[0041] The following describes the IGBT module lifetime prediction method mentioned in the embodiments of this application with reference to the accompanying drawings. Figure 2 As shown, the IGBT module lifetime prediction method includes:
[0042] S201: Construct and determine the first junction temperature change value of the IGBT module based on the first calculation model.
[0043] In some instances, IGBT modules may include specifications such as resistance values and thermal impedance.
[0044] In some instances, constructing a first pre-defined change calculation model may include:
[0045] Obtaining the first time interval Δt of the IGBT module can be understood as the time interval between two adjacent acquisition times of the IGBT module. For example, 4.075s or 0.537s.
[0046] Furthermore, the current I of the IGBT module in the first time interval is obtained, and then the power loss is calculated according to the relationship between resistance and current, P = I. 2 R determines the power loss P of the IGBT module in the first time interval.
[0047] Then, the first calculation model is constructed as shown in formula (1):
[0048]
[0049] Where, ΔT j -1 represents the sum of the junction temperature changes of the four resistors in the IGBT module during the first time interval Δt, i.e., the first junction temperature change; i represents the number of resistors in the IGBT module, i = 1, 2, 3, 4; τ th,i P represents the thermal impedance corresponding to the i-th resistor in the IGBT module; i This represents the power loss of the i-th resistor in the first time interval Δt of the IGBT module; ΔT j,i (j-1) represents the junction temperature change of the i resistors in the IGBT module in the time interval preceding the first time interval Δt. If there is no preceding time interval, then ΔT... j,i (j-1)=0.
[0050] It is understandable that the first calculation model uses the resistance values and power loss P corresponding to each resistor in the IGBT module. i Thermal resistance τ th,i After calculating the junction temperature change value corresponding to each resistor separately, the first junction temperature change value ΔT of the IGBT module is determined based on the sum of the junction temperature change values corresponding to each resistor. j -1.
[0051] Therefore, the first junction temperature change value ΔT of the IGBT module can be determined according to the first calculation model shown in formula (1). j -1.
[0052] S202: Determine whether the first junction temperature change value of the IGBT module is less than 125℃.
[0053] In some optional instances, this corresponds to the first junction temperature change value ΔT of the IGBT module. j -1 satisfies ΔT j <125℃, can be further converted to S206, based on the first junction temperature change value ΔT j The -1 and Coffin-Manson lifetime models predict the lifetime of IGBT modules.
[0054] The first junction temperature change value ΔT corresponding to the IGBT module j -1 does not satisfy ΔT jIf the temperature is less than 125℃, proceed to S203 to further construct and determine the second junction temperature change value of the IGBT module based on the second calculation model.
[0055] For example, Table 1 shows the first junction temperature change value ΔT of the IGBT module determined based on the first calculation model. j -1.
[0056] Table 1
[0057] Serial Number Δt / s I / A P / W <![CDATA[ΔT j ]]> 1 4.578 177.5389 22.06404 6.726747 2 0.005 160.1351 17.95027 15.85598 3 0.005 145.2136 14.76089 37.33369 4 0.013 153.1002 16.40777 41.29848 5 0.008 186.6514 24.38713 146.1504 6 0.028 203.6547 29.03267 213.2787 7 0.765 190.7379 25.46667 44.52628
[0058] It is understandable that the time interval Δt shown in sequence number 1 is 4.578s, and the time interval Δt shown in sequence number 2 is 0.005s. Obviously, the difference between these adjacent time intervals is quite large, which can easily affect the calculation of the first junction temperature change value ΔT of the IGBT module by the first calculation model. j -1. Furthermore, as can be seen from numbers 2 to 4, when the time interval changes relatively small, the first junction temperature change value ΔT j -1 represents a gradual increase until the first junction temperature change value ΔT shown in number 5 is reached. j -1 is 146.1504, which is greater than 125℃. This indicates that for the first calculation model, when the time interval is not fixed or differs significantly, the calculation of the first junction temperature change value ΔT of the IGBT module will be affected. j The effect of -1 is cumulative.
[0059] Therefore, in Table 1, item 5, when the first time interval Δt is 0.008s, determines the first junction temperature change value ΔT of the IGBT module based on the first calculation model. j -1 is 146.1504, which is greater than 125℃. In Table 1, item 6, based on the first calculation model, determines the first junction temperature change value ΔT of the IGBT module when the first time interval Δt is 0.028. j -1 is 213.2787, which is greater than 125℃. Obviously, given that the maximum value of ΔTj for the IGBT module is 125℃, the ΔTj calculated by the first calculation model in items 5 and 6 cannot be used as a reference. Therefore, it is necessary to further determine the second junction temperature change value of the IGBT module based on the second calculation model.
[0060] S203: Construct and determine the second junction temperature change value of the IGBT module based on the second calculation model.
[0061] In some instances, constructing a second computational model may include:
[0062] Based on the above S201, the IGBT module's first time interval Δt, the IGBT module's power loss P within the first time interval Δt, the IGBT module's resistance R, and the IGBT module's thermal impedance τ are obtained.th ,
[0063] Construct a second computational model as shown in formula (2):
[0064]
[0065] Where, ΔT j -2 represents the second junction temperature change of the IGBT module within the first time interval Δt; R represents the resistance value of the IGBT module; P represents the power loss of the IGBT module within the first time interval Δt; τ th This is expressed as the thermal impedance corresponding to the IGBT module; ΔT j (j-1) represents the junction temperature change of the IGBT module in the time interval preceding the first time interval Δt. If there is no preceding time interval, then ΔT... j (j-1)=0. Here, the resistance value corresponding to the IGBT module represents the resistance value and R of each resistor in the IGBT module; the power loss of the IGBT module in the first time interval Δt represents the power consumption and P of each resistor in the IGBT module; and the thermal impedance corresponding to the IGBT module represents the thermal impedance and τ of each resistor in the IGBT module. th .
[0066] It is understandable that the second calculation model is based on the resistance value and R of each resistor, the power loss and P, and the thermal impedance and τ. th The second junction temperature change value ΔT of the IGBT module was calculated. j -2.
[0067] Therefore, the second junction temperature change value ΔT of the IGBT module can be determined according to the second calculation model shown in formula (2). j -2.
[0068] S204: Determine whether the second junction temperature change value of the IGBT module is less than 125℃.
[0069] In some optional instances, this corresponds to the second junction temperature change value ΔT of the IGBT module. j -2 satisfies ΔT j <125℃, can be further converted to S206, based on the second junction temperature change value ΔT j -2 and the Coffin-Manson lifetime model predict the lifetime of IGBT modules.
[0070] The second junction temperature change value ΔT corresponding to the IGBT module j -2 does not satisfy ΔT jIf the temperature is less than 125℃, proceed to step S205 to further establish a first linear relationship between the power loss P of the IGBT module in the second time interval when the junction temperature change value is less than the first junction temperature threshold and the third junction temperature change value, and determine the fourth junction temperature change value of the IGBT module in the first time interval.
[0071] For example, according to the first junction temperature change value ΔT in Table 1 j -1 does not satisfy ΔT j For temperatures below 125℃, Table 2 shows the second junction temperature variation value ΔT of the IGBT module determined based on the second calculation model. j -2.
[0072] Table 2
[0073]
[0074]
[0075] It is understandable that, based on the first calculation model, ΔT is determined in Table 1 above. j For items 5 and 6, which have a temperature greater than 125℃, the second junction temperature change value ΔT of the IGBT module can be determined again based on the second calculation model. j -2.
[0076] For example, in item 5 of Table 2, when the first time interval is 0.008, the second junction temperature change value ΔT of the IGBT module is determined based on the first calculation model. j -2 is 46.94772, which is less than 125℃. Therefore, by using the second calculation model again, the calculation of ΔT by the first calculation model can be effectively avoided. j The problem of inaccuracy.
[0077] In some instances, if the second junction temperature change value ΔT is determined using the second calculation model... j If -2 is still greater than 125℃, such as item 6 in Table 2, then further construction of the IGBT module is needed at ΔT. j The first linear relationship between the power loss P at <125℃ and the third junction temperature change value is used to determine the fourth junction temperature change value of the IGBT module in the first time interval.
[0078] S205: Establish the first linear relationship between the power loss of the IGBT module and the third junction temperature change value, and determine the fourth junction temperature change value of the IGBT module.
[0079] In some optional instances, this corresponds to the second junction temperature change value ΔT of the IGBT module determined in S204. j -2 does not satisfy ΔT j <125℃, obtain ΔT of the IGBT module within multiple second time intervals of the historical time interval.j The first linear relationship between the power loss P at <125℃ and the third junction temperature change is then established. Based on this first linear relationship, the fourth junction temperature change ΔT of the IGBT module is determined. j -3.
[0080] In some instances, refer to Table 2, the IGBT module is constructed in ΔT j The first linear relationship between the power loss P at <125℃ and the change in the third junction temperature can include:
[0081] Get ΔT j At least three second time intervals corresponding to <125℃ (e.g., at least three of the historical time intervals corresponding to serial numbers 2 to 5 in Table 2);
[0082] Determine the third junction temperature change value and power loss P corresponding to multiple second time intervals;
[0083] Based on the third junction temperature change value and power loss P corresponding to multiple second time intervals, a first linear relationship between power loss P and third junction temperature change value is constructed.
[0084] Based on the first linear relationship between the power loss P and the third junction temperature change value and the power loss corresponding to the first time interval, the fourth junction temperature change value ΔT of the IGBT module is determined. j -3.
[0085] It is understandable that the first linear relationship can represent the proportional relationship between the third junction temperature change and the power loss.
[0086] For example, ΔT corresponding to number 6 j At a temperature ≥125℃, multiple second time intervals are obtained for numbers 5, 4, and 3. Based on these second time intervals, the third junction temperature change values corresponding to numbers 5, 4, and 3 are obtained as 46.94772, 41.29848, and 41.29848, respectively, and the corresponding power loss P is obtained as 24.38713, 16.40777, and 14.76089, respectively. Therefore, based on the third junction temperature change values and power loss P corresponding to numbers 5, 4, and 3, a first linear relationship between power loss P and the third junction temperature change value is established. Then, based on the first linear relationship and the power loss of number 6 (29.03267), the fourth junction temperature change value for number 6 is determined.
[0087] For example, according to the second junction temperature change value ΔT in Table 2 j -2 does not satisfy ΔT j At temperatures below 125℃, the IGBT modules constructed as shown in Table 3 are in ΔT... jThe first linear relationship between the power loss P at <125℃ and the third junction temperature change value is used to determine the fourth junction temperature change value of the IGBT module.
[0088] Table 3
[0089] Serial Number Δt / s I / A P / W <![CDATA[ΔT j ]]> 1 4.578 177.5389 22.06404 6.726747 2 0.005 160.1351 17.95027 15.85598 3 0.005 145.2136 14.76089 37.33369 4 0.013 153.1002 16.40777 41.29848 5 0.008 186.6514 24.38713 46.94772 6 0.028 203.6547 29.03267 50.29745 7 0.765 190.7379 25.46667 44.52628
[0090] It is understandable that, based on the second calculation model, ΔT is determined in Table 2 above. j Serial number 6, exceeding 125℃. This can be achieved again by constructing an IGBT module at ΔT. j The first linear relationship between the power loss P at <125℃ and the third junction temperature change value is used to determine the fourth junction temperature change value ΔT of the IGBT module. j -3.
[0091] For example, in item 6 of Table 2, when the first time interval is 0.028s, the fourth junction temperature change value ΔT of the IGBT module can be determined based on the first linear relationship between the power loss P and the third junction temperature change value. j -3 is 50.29745, which is less than 125℃.
[0092] S206: Predict the lifetime of IGBT modules based on the Coffin-Manson lifetime model.
[0093] In some instances, the Coffin-Manson lifetime model is shown in equation (3):
[0094]
[0095] Where α, n, E a , k and T m All are Coffin-Manson lifetime model coefficients; ΔT j This refers to the junction temperature change value of the IGBT module, such as the first junction temperature change value ΔT mentioned above. j -1. Second junction temperature change value ΔT j -2 and the fourth junction temperature change value ΔT j -3.
[0096] Thus, the junction temperature change ΔT of the IGBT module can be used as a reference. j The Coffin-Manson lifetime model is used to predict the lifetime of IGBT modules. This avoids the situation where the first calculation model miscalculates the junction temperature change value of the IGBT module to be predicted due to long or irregular time intervals for collecting junction temperature data from the IGBT module, thus affecting the inaccuracy of the IGBT module lifetime prediction.
[0097] For example Figure 3The time interval shown is related to the junction temperature change (ΔT) of the IGBT module. j The graph shows the relationship between the IGBT module and its junction temperature. The horizontal axis represents the time interval (s), and the vertical axis represents the junction temperature change of the IGBT module (ΔT). j The temperature range is 0 to 60℃. This is understandable. Figure 3 As can be seen, the IGBT module lifespan prediction method provided in this application embodiment can stabilize the junction temperature change value of the IGBT module between 0 and 60 degrees Celsius, even when the historical time intervals for multiple collections of the junction temperature of the IGBT module are long or the historical time intervals are different. There are no abnormalities. Therefore, the junction temperature change value of the IGBT module can be calculated more accurately through the above scheme, thereby predicting the lifespan of the IGBT module.
[0098] Figure 4 According to some embodiments of this application, a schematic diagram of the structure of a detection device 100 is shown. For example... Figure 4 As shown, the detection device 100 includes: a first calculation model, a second calculation model, and a first lifetime prediction model (corresponding to the Coffin-Manson lifetime model mentioned above).
[0099] The first calculation model is used to determine the first junction temperature change value of the IGBT module corresponding to the first time interval; for example, in S201 above, the first junction temperature change value of the IGBT module is determined based on the first preset calculation model.
[0100] The second calculation model is used to determine the second junction temperature change value of the IGBT module corresponding to the first time interval when the first junction temperature change value is greater than or equal to the preset first junction temperature threshold; for example, S202 and S203 above correspond to the first junction temperature change value ΔT. j -1 does not satisfy ΔT j <125℃, based on the second calculation model, determine the second junction temperature change value of the IGBT module.
[0101] The first lifetime prediction model is used to determine the target predicted lifetime of the corresponding IGBT module based on the fourth junction temperature change value when the second junction temperature change value is greater than or equal to the first junction temperature threshold; for example, S204-S206 above correspond to the second junction temperature change value ΔT. j -2 is still greater than 125℃, further constructing IGBT modules in ΔT j The first linear relationship between the power loss P at <125℃ and the third junction temperature change value is used to determine the fourth junction temperature change value of the IGBT module in the first time interval.
[0102] In some instances, the determination of the fourth junction temperature change value includes: obtaining the third junction temperature change value corresponding to multiple second time intervals and the power loss corresponding to multiple second time intervals, wherein the third junction temperature change value is calculated before the first junction temperature change value and the third junction temperature change value is less than the first junction temperature threshold; constructing a first linear relationship based on multiple power losses and multiple third junction temperature change values; and determining the fourth junction temperature change value corresponding to the first time interval based on the first linear relationship and the power loss corresponding to the first time interval.
[0103] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Rather, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.
[0104] It should be noted that the units / modules mentioned in the various device embodiments of the present invention are all logical units / modules. Physically, a logical unit / module can be a physical unit / module, a part of a physical unit / module, or a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important factor; the combination of functions implemented by these logical units / modules is the key to solving the technical problem proposed by the present invention. Furthermore, to highlight the innovative aspects of the present invention, the above-described device embodiments of the present invention have not introduced units / modules that are not closely related to solving the technical problem proposed by the present invention. This does not mean that the above-described device embodiments do not contain other units / modules.
[0105] It should be noted that in the examples and description of this patent, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0106] Although the invention has been illustrated and described with reference to certain embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the scope of the invention.
Claims
1. A method for predicting the lifespan of an IGBT module, characterized in that, The method is applied to a detection device, which includes a first calculation model, a second calculation model, and a first lifetime prediction model, wherein the method includes: The first junction temperature change value of the IGBT module corresponding to the first time interval is determined by the first calculation model; If the first junction temperature change value is greater than or equal to the preset first junction temperature threshold, the second calculation module determines the second junction temperature change value of the IGBT module corresponding to the first time interval. If the second junction temperature change value is greater than or equal to the first junction temperature threshold, obtain the third junction temperature change value corresponding to the multiple second time intervals and the power loss corresponding to the multiple second time intervals, wherein the third junction temperature change value is calculated before the first junction temperature change value and the third junction temperature change value is less than the first junction temperature threshold. A first linear relationship is constructed based on multiple power loss values and multiple third junction temperature change values; Based on the first linear relationship and the power loss corresponding to the first time interval, a fourth junction temperature change value corresponding to the first time interval is determined, wherein the fourth junction temperature change value is less than the first junction temperature threshold. The fourth junction temperature change value is input into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module.
2. The method according to claim 1, characterized in that, The method further includes: If the first junction temperature change value is less than the first junction temperature threshold, the first junction temperature change value is input into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module. Alternatively, if the second junction temperature change value is less than the first junction temperature threshold, the second junction temperature change value is input into the first lifetime prediction model to obtain the target predicted lifetime of the corresponding IGBT module.
3. The method according to claim 1, characterized in that, The preset first junction temperature threshold includes 125°C.
4. The method according to claim 1, characterized in that, The method further includes: Obtain the specifications of the IGBT module, including resistance and thermal impedance. The power loss of the IGBT module during the first time interval is determined based on the current of the IGBT module during the first time interval. Based on the specified parameters, the power loss, and the first time interval, construct the first calculation model or the second calculation model.
5. The method according to claim 4, characterized in that, The first calculation model determines the first junction temperature change value using the following formula: Where, ΔT j -1 represents the first junction temperature change value, Δt represents the first time interval, i = 1, 2, 3, 4, representing the number of resistors included in the IGBT module, and τ th,i P represents the thermal impedance corresponding to the i-th resistor in the IGBT module. i ΔT represents the power loss of the i-th resistor in the IGBT module during the first time interval Δt. j,i (j-1) represents the junction temperature change value of the i resistors of the IGBT module in the time interval preceding the first time interval.
6. The method according to claim 4, characterized in that, The second calculation model determines the second junction temperature change value using the following formula: Where, ΔT j -2 represents the second junction temperature change value, R represents the resistance value corresponding to the IGBT module, Δt represents the first time interval, and τ th P represents the thermal impedance of the IGBT module, and P represents the power loss of the IGBT module during the first time interval Δt. j,i (j-1) represents the junction temperature change value of the IGBT module in the time interval preceding the first time interval.
7. The method according to claim 1, characterized in that, The first time interval is determined by randomly collecting data at a first and second time point, and the time interval between the first and second time points is used to determine the first time interval.
8. The method according to claim 1, characterized in that, The duration of both the first time interval and the second time interval is less than a preset first duration threshold.
9. The method according to claim 1, characterized in that, The first linear relationship includes: the third junction temperature change value is proportional to the power loss corresponding to the plurality of second time intervals.
10. A detection device, characterized in that, The detection device includes: The first calculation model is used to determine the first junction temperature change value of the IGBT module corresponding to the first time interval. The second calculation model is used to determine the second junction temperature change value of the IGBT module corresponding to the first time interval when the first junction temperature change value is greater than or equal to a preset first junction temperature threshold. A first lifetime prediction model is used to determine the target predicted lifetime of the corresponding IGBT module based on a fourth junction temperature change value when the second junction temperature change value is greater than or equal to the first junction temperature threshold. The fourth junction temperature change value is less than the first junction temperature threshold. The fourth junction temperature change value is determined based on a first linear relationship and the power loss corresponding to the first time interval. The first linear relationship is determined based on third junction temperature change values corresponding to multiple second time intervals and the power loss corresponding to the multiple second time intervals. The third junction temperature change value is calculated before the first junction temperature change value and is less than the first junction temperature threshold.