An IGBT module health condition monitoring method and device

Abstract

The application discloses an IGBT module health state monitoring method and device, the method comprises the following steps: acquiring the first junction temperature and the first power loss of the IGBT chip according to the working parameters of the converter; collecting the first shell temperature and the second shell temperature of the IGBT module substrate, and calculating the equivalent thermal resistance ratio between the first equivalent thermal resistance and the second equivalent thermal resistance corresponding to the shell temperature according to the first junction temperature and the first power loss; the measuring points of the first shell temperature and the second shell temperature are different from the distance of the IGBT chip; when the increment of the equivalent thermal resistance ratio is greater than the first threshold value, it is determined that the solder layer of the IGBT module is invalid; in addition, the on-voltage drop change is calculated according to the equivalent thermal resistance ratio, and whether the bonding wire of the IGBT module is invalid is judged according to the on-voltage drop change. By adopting the embodiment of the application, the influence caused by the uneven distribution of the radiator surface temperature can be offset, and the monitoring accuracy of the IGBT module health state is improved.

Description

Technical Field

[0001] This invention relates to the field of IGBT condition monitoring, and more particularly to a method and apparatus for monitoring the health status of IGBT modules. Background Technology

[0002] With the continuous growth of installed capacity in new energy power generation systems, the requirements for the cost, efficiency, and reliability of power converters are becoming increasingly stringent to ensure a continuous and stable power supply. Insulated Gate Bipolar Transistor (IGBT) modules, as core components of power converters, suffer from high failure rates due to IGBT failures. When IGBT modules repeatedly switch on and off, repeated thermal shocks can cause failures or fatigue effects, impacting the reliability of the entire device or system. Therefore, health monitoring methods for power modules are crucial for improving IGBT reliability. Common failure modes of IGBT modules include solder layer fatigue and bond wire breakage. Solder layer cracks reduce the heat conduction area within the solder layer, worsening the internal heat conduction of the IGBT module and exacerbating the unevenness of the substrate surface temperature distribution. Consequently, the equivalent thermal resistance changes over time during solder layer aging. Furthermore, bond wire breakage leads to an increase in saturation voltage drop, thereby increasing the total conduction loss of the switching transistor chip. Although the aging process of IGBT modules is mainly caused by thermal stress, leading to changes in power loss and temperature, thermal parameters are rarely used as characteristic quantities for IGBT module condition monitoring. This is partly because important thermal parameters such as junction temperature are difficult to obtain accurately during IGBT module operation and aging, while easily measurable parameters have not received sufficient attention in IGBT module condition monitoring. Summary of the Invention

[0003] This invention provides a method and apparatus for monitoring the health status of IGBT modules, thereby solving the technical problem that existing technologies cannot accurately monitor the health status of IGBT modules due to the difficulty in measuring thermal parameters.

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a method for monitoring the health status of an IGBT module, comprising:

[0005] Based on the operating parameters of the converter, obtain the first junction temperature and first power loss of the IGBT chip;

[0006] The first and second case temperatures of the IGBT module substrate are collected, and the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature is calculated based on the first junction temperature and the first power loss. Wherein, the first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip.

[0007] Determine whether the increment of the equivalent thermal resistance ratio is greater than a first threshold.

[0008] When the increment of the equivalent thermal resistance ratio is greater than the first threshold, the solder layer of the IGBT module is deemed to have failed.

[0009] Based on the equivalent thermal resistance ratio, the change in on-state voltage drop is calculated, and based on the change in on-state voltage drop, it is determined whether the IGBT module has experienced bond wire failure.

[0010] This invention measures the case temperature at different locations from the IGBT chip, and calculates the corresponding equivalent thermal resistance and equivalent thermal resistance ratio by combining the first junction temperature and the first power loss. This offsets the impact of uneven temperature distribution on the heat sink surface and improves the accuracy of monitoring the health status of the IGBT module. In addition, detecting the case temperature, which is a non-electrical quantity, can achieve electrical isolation from the power circuit. Furthermore, the equivalent thermal resistance ratio can be used to determine solder layer failure and bond wire failure, reducing monitoring costs and difficulty.

[0011] Furthermore, obtaining the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter specifically involves:

[0012] Based on the converter's operating parameters, obtain the first junction temperature and first power loss of the IGBT chip from the IGBT module test manual.

[0013] This invention uses a lookup table to obtain the first junction temperature and the first power loss, which reduces the complexity of the health status monitoring algorithm and avoids the technical problem of inaccurate monitoring of the health status of IGBT modules due to the difficulty in measuring thermal parameters.

[0014] Further, the step of calculating the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss is specifically as follows:

[0015] The first equivalent thermal resistance is calculated using the equivalent thermal resistance calculation formula based on the first case temperature and the first power loss; the second equivalent thermal resistance is calculated using the equivalent thermal resistance calculation formula based on the second case temperature and the first power loss; wherein, the first power loss is the power loss of the IGBT chip at the first junction temperature;

[0016] The equivalent thermal resistance ratio is calculated based on the first equivalent thermal resistance and the second equivalent thermal resistance.

[0017] Furthermore, the formula for calculating the equivalent thermal resistance is as follows:

[0018]

[0019] Among them, R eqC0 T is the first equivalent thermal resistance or the second equivalent thermal resistance. C The first or second shell temperature, T A For external ambient temperature, P loss (T J0 ) represents the first power loss.

[0020] This invention calculates a first equivalent thermal resistance corresponding to a first case temperature and a second equivalent thermal resistance corresponding to a second case temperature, and then obtains the equivalent thermal resistance ratio using the two equivalent thermal resistances. This ratio is used to subsequently determine the solder layer failure of the IGBT module, thus offsetting the measurement error caused by uneven case temperature distribution and improving monitoring accuracy.

[0021] Further, the step of calculating the change in on-state voltage drop based on the equivalent thermal resistance ratio, and determining whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop, specifically involves:

[0022] Based on the aforementioned equivalent thermal resistance ratio, the third equivalent thermal resistance and the junction-shell thermal resistance are obtained;

[0023] Based on the third equivalent thermal resistance and the junction-shell thermal resistance, the second power loss is obtained by looking up the table, and based on the second power loss and the conduction loss, the change in conduction voltage drop is calculated.

[0024] Determine whether the change in on-state voltage drop is greater than the second threshold.

[0025] When the change in on-state voltage drop exceeds the second threshold, the IGBT module bonding wire is deemed to have failed.

[0026] When determining the failure of the bonding wire in an IGBT module, this invention updates the second power loss after obtaining the third equivalent thermal resistance and the junction-shell thermal resistance through the equivalent thermal resistance ratio. This eliminates the increase in power consumption caused by junction temperature changes, thereby making the calculated change in on-state voltage drop more accurate and improving the accuracy of monitoring.

[0027] Further, the step of obtaining the third equivalent thermal resistance and the junction-shell thermal resistance based on the equivalent thermal resistance ratio specifically involves:

[0028] Based on the equivalent thermal resistance ratio, the third equivalent thermal resistance and the junction thermal resistance corresponding to the equivalent thermal resistance ratio are obtained in real time from the lookup table of offline experimental records.

[0029] Further, the step of obtaining the second power loss by looking up a table based on the third equivalent thermal resistance and the junction-shell thermal resistance, and calculating the change in on-state voltage drop based on the second power loss and the conduction loss, specifically involves:

[0030] The second junction temperature is calculated based on the third equivalent thermal resistance and the junction-shell thermal resistance.

[0031] Based on the second junction temperature, obtain the second power loss corresponding to the second junction temperature from the IGBT module test manual;

[0032] The ratio between the second power loss and the on-state voltage drop is calculated to obtain the change in the on-state voltage drop.

[0033] This invention calculates the changed second junction temperature based on the third equivalent thermal resistance and the junction-shell thermal resistance, and then updates the power loss based on the second junction temperature to obtain the second power loss. Furthermore, it takes into account the increase in power loss caused by the change in junction temperature, thus better reflecting the changes in the thermal behavior of the IGBT module caused by the aging of the bonding wires and improving the monitoring accuracy.

[0034] Further, the calculation of the second junction temperature based on the third equivalent thermal resistance and the junction-shell thermal resistance specifically involves:

[0035] The power loss ratio is calculated based on the third equivalent thermal resistance and the equivalent thermal resistance relationship.

[0036] Based on the power loss ratio and the junction-shell thermal resistance, combined with the collected external ambient temperature, the second junction temperature is calculated; wherein, the expression for the second junction temperature is:

[0037] T J =P loss (T J )·(R thJC +R eqC )+T A ;

[0038] Among them, P loss (T J R represents the power loss corresponding to the second junction temperature. thJC For the junction thermal resistance, R eqC For the third equivalent thermal resistance, T A The external ambient temperature.

[0039] Furthermore, the equivalent thermal resistance relationship is as follows:

[0040]

[0041] Where s is the power loss ratio, R eqC0For the initial equivalent thermal resistance, R eqC For the third equivalent thermal resistance, T C The third shell temperature, T A For external ambient temperature, P loss0 (T J0 P represents the first power loss. loss (T J (to be related to junction temperature T) J The corresponding power loss.

[0042] On the other hand, embodiments of the present invention also provide an IGBT module health status monitoring device, including: a first parameter acquisition module, a shell temperature acquisition module, a first judgment module, and a first confirmation module;

[0043] The first parameter acquisition module is used to acquire the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter.

[0044] The case temperature acquisition module is used to acquire the first case temperature and the second case temperature of the IGBT module substrate, and calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss; wherein, the first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip.

[0045] The first judgment module is used to determine whether the increment of the equivalent thermal resistance ratio is greater than a first threshold.

[0046] The first confirmation module is used to determine that the solder layer of the IGBT module has failed when the increment of the equivalent thermal resistance ratio is greater than a first threshold.

[0047] The second judgment module is used to calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature after the case temperature acquisition module calculates the change in on-state voltage drop based on the equivalent thermal resistance ratio, and to determine whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop.

[0048] This invention measures the case temperature at different locations from the IGBT chip, and calculates the corresponding equivalent thermal resistance and equivalent thermal resistance ratio by combining the first junction temperature and the first power loss. This offsets the impact of uneven temperature distribution on the heat sink surface and improves the accuracy of monitoring the health status of the IGBT module. In addition, detecting the case temperature, which is a non-electrical quantity, can achieve electrical isolation from the power circuit, reducing monitoring costs and difficulty. Attached Figure Description

[0049] Figure 1This is a flowchart illustrating one embodiment of the IGBT module health status monitoring method provided by the present invention.

[0050] Figure 2 A schematic diagram of one embodiment of the temperature sensor installation position provided by the present invention;

[0051] Figure 3 A flowchart illustrating another embodiment of the IGBT module health status monitoring method provided in this invention.

[0052] Figure 4 A flowchart illustrating another embodiment of the IGBT module health status monitoring method provided in this invention.

[0053] Figure 5 This is a schematic diagram of the structure of one embodiment of the thermal model of the IGBT module provided in this invention.

[0054] Figure 6 This is a schematic diagram of one embodiment of the IGBT module health status monitoring device provided in this invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] Please refer to Figure 1 This is a flowchart illustrating one embodiment of the IGBT module health status monitoring method provided by the present invention, mainly including steps 101-104, as follows:

[0058] Step 101: Obtain the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter.

[0059] In this embodiment, obtaining the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter specifically involves obtaining the first junction temperature and first power loss of the IGBT chip from the IGBT module test manual based on the operating parameters of the converter.

[0060] The operating parameters include: operating current amplitude, switching frequency, modulation index, and ambient temperature.

[0061] In this embodiment, the first junction temperature and the first power loss are the junction temperature and power loss of the new IGBT module in a healthy state, respectively, and do not change with the aging of the IGBT module. Before obtaining the first junction temperature and the first power loss of the IGBT chip from the IGBT module test manual, the values ​​of the first junction temperature and the first power loss can be obtained by using the IGBT module datasheet, power loss calculation equation, and thermal model of the IGBT module and heat sink through an iterative electrothermal coupling model, and stored in the power loss table in the IGBT module test manual for easy retrieval.

[0062] Step 102: Collect the first and second case temperatures of the IGBT module substrate, and calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss; wherein, the first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip.

[0063] In this embodiment, the case temperature is detected at different distances from the IGBT chip on the IGBT module substrate, rather than at a single location on the IGBT module substrate. This is to take into account the impact of uneven temperature distribution on the heat sink surface, and to eliminate the error caused by uneven temperature distribution on the heat sink surface by using the equivalent thermal resistance ratio.

[0064] In this embodiment, the distance between the second case temperature detection point and the IGBT chip can be greater than the distance between the first case temperature monitoring point and the IGBT chip.

[0065] Please refer to Figure 2 This is a schematic diagram of one embodiment of the temperature sensor installation position provided by the present invention. The case temperature can be detected at different distances from the IGBT chip by installing two or more temperature sensors at different distances to the same IGBT chip, and the non-uniformity of the case temperature distribution can be evaluated by the equivalent thermal resistance ratio at the two detection points. Among them, the case temperature above the IGBT chip is more sensitive to changes in power loss than the case temperature at a position farther away from the IGBT chip.

[0066] In this embodiment, the expression for the equivalent thermal resistance ratio is:

[0067]

[0068] Among them, R eqCc R is the first equivalent thermal resistance. eqCs This is the second equivalent thermal resistance.

[0069] Step 103: Determine whether the increment of the equivalent thermal resistance ratio is greater than the first threshold.

[0070] In this embodiment, the increment of the equivalent thermal resistance ratio can be calculated based on the equivalent thermal resistance ratio obtained in step 102 and the equivalent thermal resistance ratio when the IGBT module is in a healthy state; wherein, the expression for the increment of the equivalent thermal resistance ratio is:

[0071]

[0072] Where r0 is the equivalent thermal resistance ratio when the IGBT module is in a healthy state.

[0073] Step 104: When the increment of the equivalent thermal resistance ratio is greater than the first threshold, the solder layer of the IGBT module is deemed to have failed.

[0074] In this embodiment, the value of the first threshold is determined according to the model of the IGBT module. When the model of the IGBT module is CM400DY-12NF, the first threshold can be 15%-20%.

[0075] Step 105: Calculate the change in on-state voltage drop based on the equivalent thermal resistance ratio, and determine whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop.

[0076] Please refer to Figure 3 This is a flowchart illustrating another embodiment of the IGBT module health status monitoring method provided in this invention. Figure 3 and Figure 1 The main difference is that, Figure 3 Including steps 201-202, as follows:

[0077] In this embodiment, step 102 specifically includes steps 201 and 202.

[0078] Step 201: Calculate the first equivalent thermal resistance using the equivalent thermal resistance calculation formula based on the first case temperature and the first power loss; calculate the second equivalent thermal resistance using the equivalent thermal resistance calculation formula based on the second case temperature and the first power loss; wherein, the first power loss is the power loss of the IGBT chip at the first junction temperature.

[0079] In this embodiment, the formula for calculating the equivalent thermal resistance is:

[0080]

[0081] Among them, R eqC0 T is the first equivalent thermal resistance or the second equivalent thermal resistance. C The first or second shell temperature, T A For external ambient temperature, P loss (T J0 ) represents the first power loss.

[0082] Step 202: Calculate the equivalent thermal resistance ratio based on the first equivalent thermal resistance and the second equivalent thermal resistance.

[0083] In this embodiment, the equivalent thermal resistance ratio changes only with the aging process of the solder layer and is independent of the operating conditions of the IGBT module. Therefore, the relationship between the equivalent thermal resistance ratio and the equivalent thermal resistance, as well as the relationship between the equivalent thermal resistance ratio and the equivalent thermal resistance of the junction, can be obtained relatively easily.

[0084] This invention calculates a first equivalent thermal resistance corresponding to a first case temperature and a second equivalent thermal resistance corresponding to a second case temperature, and then obtains the equivalent thermal resistance ratio using the two equivalent thermal resistances. This ratio is used to subsequently determine the solder layer failure of the IGBT module, thus offsetting the measurement error caused by uneven case temperature distribution and improving monitoring accuracy.

[0085] Please refer to Figure 4 The above is a flowchart illustrating another embodiment of the IGBT module health status monitoring method provided by the present invention, mainly including steps 301-304, as follows:

[0086] In this embodiment, step 105 specifically includes steps 301 to 304.

[0087] Step 301: Obtain the third equivalent thermal resistance and the junction thermal resistance based on the equivalent thermal resistance ratio.

[0088] In this embodiment, obtaining the third equivalent thermal resistance and the junction-shell thermal resistance based on the equivalent thermal resistance ratio specifically involves: obtaining the third equivalent thermal resistance and the junction-shell thermal resistance corresponding to the equivalent thermal resistance ratio in real time from a lookup table of offline experimental records based on the equivalent thermal resistance ratio.

[0089] Step 302: Based on the third equivalent thermal resistance and the junction-shell thermal resistance, look up the table to obtain the second power loss, and calculate the change in conduction voltage drop based on the second power loss and the conduction loss.

[0090] In this embodiment, the step of obtaining the second power loss by looking up a table based on the third equivalent thermal resistance and the junction-to-case thermal resistance, and calculating the change in on-state voltage drop based on the second power loss and the conduction loss, specifically involves: calculating the second junction temperature based on the third equivalent thermal resistance and the junction-to-case thermal resistance; obtaining the second power loss corresponding to the second junction temperature from the IGBT module test manual based on the second junction temperature; and calculating the ratio between the second power loss and the on-state voltage drop to obtain the change in on-state voltage drop.

[0091] This invention calculates the changed second junction temperature based on the third equivalent thermal resistance and the junction-shell thermal resistance, and then updates the power loss based on the second junction temperature to obtain the second power loss. Furthermore, it takes into account the increase in power loss caused by the change in junction temperature, thus better reflecting the changes in the thermal behavior of the IGBT module caused by the aging of the bonding wires and improving the monitoring accuracy.

[0092] In this embodiment, the calculation of the second junction temperature based on the third equivalent thermal resistance and the junction-shell thermal resistance specifically involves:

[0093] The power loss ratio is calculated based on the third equivalent thermal resistance and the equivalent thermal resistance relationship.

[0094] Based on the power loss ratio and the junction-shell thermal resistance, combined with the collected external ambient temperature, the second junction temperature is calculated; wherein, the expression for the second junction temperature is:

[0095] T J =P loss (T J )·(R thJC +R eqC )+T A ;

[0096] Among them, P loss (T J R represents the power loss corresponding to the second junction temperature. thJC For the junction thermal resistance, R eqC For the third equivalent thermal resistance, T A The external ambient temperature.

[0097] Please refer to Figure 5 This is a schematic diagram of the structure of an embodiment of the thermal model of an IGBT module provided in this invention. In this embodiment, FWD is the freewheeling diode of the IGBT, the equivalent thermal resistance between the IGBT chip and the IGBT module casing is the junction-to-case thermal resistance, and the equivalent thermal resistance between the IGBT module casing and the external environment is the third equivalent thermal resistance.

[0098] In this embodiment, the equivalent thermal resistance relationship is:

[0099]

[0100] Where s is the power loss ratio, R eqC0 For the initial equivalent thermal resistance, R eqC For the third equivalent thermal resistance, T C The third shell temperature, T A For external ambient temperature, P loss0 (T J0 P represents the first power loss. loss (T J(to be related to junction temperature T) J The corresponding power loss.

[0101] Step 303: Determine whether the change in the on-state voltage drop is greater than the second threshold.

[0102] In this embodiment, the second threshold is determined according to the model of the IGBT module. When the model of the IGBT module is CM400DY-12NF, the second threshold can be 10%-20%. When the change in on-state voltage drop exceeds the range of the second threshold, the bonding wire of the IGBT module is considered to be faulty.

[0103] Step 304: When the change in on-state voltage drop is greater than the second threshold, the IGBT module bonding wire is deemed to have failed.

[0104] When determining the failure of the bonding wire in an IGBT module, this invention updates the second power loss after obtaining the third equivalent thermal resistance and the junction-shell thermal resistance through the equivalent thermal resistance ratio. This eliminates the increase in power consumption caused by junction temperature changes, thereby making the calculated change in on-state voltage drop more accurate and improving the accuracy of monitoring.

[0105] Please refer to Figure 6 This is a schematic diagram of an embodiment of the IGBT module health status monitoring device provided in this invention, which mainly includes: a first parameter acquisition module 401, a shell temperature acquisition module 402, a first judgment module 403, and a first confirmation module 404.

[0106] In this embodiment, the first parameter acquisition module 401 is used to acquire the first junction temperature and the first power loss of the IGBT chip based on the operating parameters of the converter.

[0107] The case temperature acquisition module 402 is used to acquire the first case temperature and the second case temperature of the IGBT module substrate, and calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss; wherein, the first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip.

[0108] The first judgment module 403 is used to determine whether the increment of the equivalent thermal resistance ratio is greater than the first threshold.

[0109] The first confirmation module 404 is used to determine that the solder layer of the IGBT module has failed when the increment of the equivalent thermal resistance ratio is greater than a first threshold.

[0110] The second judgment module 405 is used to calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature after the case temperature acquisition module 402 calculates the change in on-state voltage drop based on the equivalent thermal resistance ratio, and to determine whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop.

[0111] In this embodiment, the second judgment module 405 includes: a parameter acquisition unit, a calculation unit, a judgment unit, and a confirmation unit; wherein, the parameter acquisition unit is used to acquire the third equivalent thermal resistance and the junction-shell thermal resistance according to the equivalent thermal resistance ratio; the calculation unit is used to look up the second power loss in a table according to the third equivalent thermal resistance and the junction-shell thermal resistance, and calculate the change in conduction voltage drop according to the second power loss and the conduction loss; the judgment unit is used to determine whether the change in conduction voltage drop is greater than a second threshold; the confirmation unit is used to determine that the IGBT module bonding wire is faulty when the change in conduction voltage drop is greater than the second threshold.

[0112] This invention measures the case temperature at different locations from the IGBT chip, and calculates the corresponding equivalent thermal resistance and equivalent thermal resistance ratio by combining the first junction temperature and the first power loss. This offsets the impact of uneven temperature distribution on the heat sink surface and improves the accuracy of monitoring the health status of the IGBT module. In addition, detecting the case temperature, which is a non-electrical quantity, can achieve electrical isolation from the power circuit, reducing monitoring costs and difficulty.

[0113] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A method for monitoring the health status of an IGBT module, characterized in that, include: Based on the operating parameters of the converter, obtain the first junction temperature and first power loss of the IGBT chip; The first and second case temperatures of the IGBT module substrate are collected, and the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature is calculated based on the first junction temperature and the first power loss. The first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip. The distance between the detection point of the second case temperature and the IGBT chip is greater than the distance between the monitoring point of the first case temperature and the IGBT chip. Determine whether the increment of the equivalent thermal resistance ratio is greater than a first threshold. When the increment of the equivalent thermal resistance ratio is greater than the first threshold, the solder layer of the IGBT module is deemed to have failed. Based on the equivalent thermal resistance ratio, the change in on-state voltage drop is calculated, and based on the change in on-state voltage drop, it is determined whether the IGBT module has experienced bond wire failure. Specifically, calculating the change in on-state voltage drop based on the equivalent thermal resistance ratio and determining whether the IGBT module has experienced bond wire failure involves: obtaining the third equivalent thermal resistance and the junction-to-shell thermal resistance based on the equivalent thermal resistance ratio; obtaining the second power loss from a table based on the third equivalent thermal resistance and the junction-to-shell thermal resistance; calculating the change in on-state voltage drop based on the second power loss and the conduction loss; determining whether the change in on-state voltage drop is greater than a second threshold; and identifying IGBT module bond wire failure when the change in on-state voltage drop is greater than the second threshold. Specifically, obtaining the third equivalent thermal resistance and the junction-to-shell thermal resistance based on the equivalent thermal resistance ratio involves: obtaining the third equivalent thermal resistance and the junction-to-shell thermal resistance corresponding to the equivalent thermal resistance ratio in real time from a lookup table of offline experimental records based on the equivalent thermal resistance ratio.

2. The IGBT module health status monitoring method as described in claim 1, characterized in that, The step of obtaining the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter is specifically as follows: Based on the converter's operating parameters, obtain the first junction temperature and first power loss of the IGBT chip from the IGBT module test manual.

3. The IGBT module health status monitoring method as described in claim 1, characterized in that, The step of calculating the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss is as follows: The first equivalent thermal resistance is calculated using the equivalent thermal resistance calculation formula based on the first case temperature and the first power loss; the second equivalent thermal resistance is calculated using the equivalent thermal resistance calculation formula based on the second case temperature and the first power loss; wherein, the first power loss is the power loss of the IGBT chip at the first junction temperature; The equivalent thermal resistance ratio is calculated based on the first equivalent thermal resistance and the second equivalent thermal resistance.

4. The IGBT module health status monitoring method as described in claim 3, characterized in that, The formula for calculating the equivalent thermal resistance is: ； in, This is either the first equivalent thermal resistance or the second equivalent thermal resistance. The first shell temperature or the second shell temperature. External ambient temperature, This is the first power loss.

5. The IGBT module health status monitoring method as described in claim 1, characterized in that, The second power loss is obtained by looking up a table based on the third equivalent thermal resistance and the junction-shell thermal resistance, and the change in on-state voltage drop is calculated based on the second power loss and the conduction loss, specifically as follows: The second junction temperature is calculated based on the third equivalent thermal resistance and the junction-shell thermal resistance. Based on the second junction temperature, obtain the second power loss corresponding to the second junction temperature from the IGBT module test manual; The ratio between the second power loss and the on-state voltage drop is calculated to obtain the change in the on-state voltage drop.

6. The IGBT module health status monitoring method as described in claim 1, characterized in that, The second junction temperature is calculated based on the third equivalent thermal resistance and the junction-shell thermal resistance, specifically as follows: The power loss ratio is calculated based on the third equivalent thermal resistance and the equivalent thermal resistance relationship. Based on the power loss ratio and the junction-shell thermal resistance, combined with the collected external ambient temperature, the second junction temperature is calculated; wherein, the expression for the second junction temperature is: ； in, For the power loss corresponding to the second junction temperature, For the thermal resistance of the shell, The third equivalent thermal resistance, The external ambient temperature.

7. The IGBT module health status monitoring method as described in claim 6, characterized in that, The equivalent thermal resistance relationship is as follows: ； in, This is the power loss ratio. For the initial equivalent thermal resistance, The third equivalent thermal resistance, The third shell temperature, External ambient temperature, The first power loss, To be related to junction temperature The corresponding power loss.

8. A health status monitoring device for an IGBT module, characterized in that, include: The system comprises a first parameter acquisition module, a shell temperature acquisition module, a first judgment module, a first confirmation module, and a second judgment module. The first parameter acquisition module is used to acquire the first junction temperature and first power loss of the IGBT chip based on the operating parameters of the converter. The case temperature acquisition module is used to acquire the first case temperature and the second case temperature of the IGBT module substrate, and calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature based on the first junction temperature and the first power loss; wherein, the first case temperature is the case temperature above the IGBT chip, and the second case temperature is the case temperature at a preset distance from the IGBT chip; the distance between the detection point of the second case temperature and the IGBT chip is greater than the distance between the monitoring point of the first case temperature and the IGBT chip; The first judgment module is used to determine whether the increment of the equivalent thermal resistance ratio is greater than a first threshold. The first confirmation module is used to determine that the solder layer of the IGBT module has failed when the increment of the equivalent thermal resistance ratio is greater than a first threshold. The second judgment module is used to calculate the equivalent thermal resistance ratio between the first equivalent thermal resistance corresponding to the first case temperature and the second equivalent thermal resistance corresponding to the second case temperature after the case temperature acquisition module calculates the change in on-state voltage drop based on the equivalent thermal resistance ratio, and to determine whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop; wherein, the step of calculating the change in on-state voltage drop based on the equivalent thermal resistance ratio and determining whether the IGBT module has experienced bond wire failure based on the change in on-state voltage drop specifically involves: obtaining the third equivalent thermal resistance and the junction temperature based on the equivalent thermal resistance ratio. Thermal resistance; based on the third equivalent thermal resistance and the junction-to-shell thermal resistance, the second power loss is obtained by looking up a table, and the change in on-state voltage drop is calculated based on the second power loss and the conduction loss; it is determined whether the change in on-state voltage drop is greater than a second threshold; when the change in on-state voltage drop is greater than the second threshold, the IGBT module bonding wire is deemed to have failed; the step of obtaining the third equivalent thermal resistance and the junction-to-shell thermal resistance based on the equivalent thermal resistance ratio specifically involves: based on the equivalent thermal resistance ratio, obtaining the third equivalent thermal resistance and the junction-to-shell thermal resistance corresponding to the equivalent thermal resistance ratio in real time from the lookup table of offline experimental records.

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