Modularized multi-level converter IGBT aging monitoring method and related device

Abstract

The invention discloses a modular multilevel converter IGBT aging monitoring method and a related device. The method comprises the following steps: determining equivalent resistance and a calculation coefficient of an IGBT device; determining the collector current of the IGBT device when the system where the IGBT device is located operates stably, and calculating the device loss of the IGBT device according to the collector current and the equivalent resistance; calculating the conduction voltage drop difference of the IGBT device in the to-be-monitored period; and calculating the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the conduction voltage drop difference, and determining the aging condition of the IGBT device according to the relative thermal resistance. The method provided by the invention is simple to implement, and all devices can be rapidly monitored. Therefore, the problems that an existing method is complex to implement and the aging condition of the IGBT is difficult to monitor rapidly are solved.

Description

Technical Field

[0001] The present invention relates to the field of electronic power technology, and in particular to a modular multi-level converter IGBT aging monitoring method and related devices. Background Art

[0002] Modular multilevel converter (MMC) has the advantages of flexible operation mode, high modularity and low loss, and is widely used in flexible DC transmission projects. As the core component of the converter, the reliability of the insulated-gate bipolar transistor (IGBT) power device directly determines the long-term stable working ability and service life of the converter. Existing studies have shown that thermal failure of power devices is the main cause of failure. Both chip-level aging and package-level aging of devices will be reflected in the junction-to-case thermal resistance of the device. Therefore, the monitoring of the junction-to-case thermal resistance of the device is of great significance for the monitoring of the aging status of the device.

[0003] The key to monitoring the device's junction-to-case thermal resistance is to obtain the device's junction temperature. Currently, the junction temperature monitoring methods are mainly summarized into four types: physical contact method, optical non-contact method, thermal impedance model prediction method, and temperature-sensitive electrical parameter method. The physical contact method requires the integration of temperature measurement components inside the module, and the optical non-contact method requires the removal of the potting glue. Both methods have the disadvantages of slow response speed and susceptibility to interference. The thermal impedance model prediction method requires the establishment of an accurate thermal impedance network model, which is difficult to model. As the equipment ages, there will be a large deviation between the preset model and the actual model, which is difficult to correct later. In comparison, the temperature-sensitive electrical parameter method has the advantages of short response time, small measurement error, and easy online monitoring, making it the most potential online monitoring method for junction temperature. However, the existing temperature-sensitive electrical parameter method requires the acquisition of more parameters, and it is difficult to quickly calculate the corresponding parameter values ​​at the same time in multi-device situations such as MMC. Summary of the invention

[0004] The present invention provides a modular multi-level converter IGBT aging monitoring method and related devices, which are used to solve the problems that the existing methods are complex to implement and difficult to quickly monitor the aging of IGBTs.

[0005] In view of this, the first aspect of the present application provides a modular multi-level converter IGBT aging monitoring method, the method comprising:

[0006] Determine the equivalent resistance of the IGBT device and the calculation coefficient;

[0007] Determine the collector current of the IGBT device when the system in which the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device according to the collector current and the equivalent resistance;

[0008] Calculate the on-state voltage drop difference of the IGBT device during the monitoring cycle;

[0009] The relative thermal resistance of the IGBT device is calculated according to the calculation coefficient, the device loss and the on-state voltage drop difference, and the aging condition of the IGBT device is determined according to the relative thermal resistance.

[0010] Optionally, the calculating the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference includes:

[0011] Substituting the calculation coefficient, the device loss and the on-state voltage drop difference into a relative thermal resistance calculation formula to calculate the relative thermal resistance of the IGBT device;

[0012] Wherein, the relative thermal resistance calculation formula is:

[0013] ;

[0014] In the formula, is the relative thermal resistance, is the calculation coefficient, The device loss, is the conduction voltage drop difference.

[0015] Optionally, determining the equivalent resistance of the IGBT device and calculating the coefficient includes:

[0016] Obtain the device parameter table of the IGBT device from the IGBT device manufacturer;

[0017] Obtaining a junction temperature-saturation voltage drop curve and an equivalent resistance of the IGBT device based on the device parameter table;

[0018] The calculation coefficient is determined according to the junction temperature-saturation voltage drop curve.

[0019] Optionally, determining the aging condition of the IGBT device according to the relative thermal resistance includes:

[0020] The variation trend of the relative thermal resistance is determined according to the relative thermal resistance of a plurality of cycles to be detected, thereby determining the aging condition of the IGBT device according to the variation trend.

[0021] A second aspect of the present application provides a modular multi-level converter IGBT aging monitoring system, the system comprising:

[0022] A first calculation unit, used to determine an equivalent resistance of an IGBT device and a calculation coefficient;

[0023] A second calculation unit is used to determine the collector current of the IGBT device when the system in which the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device according to the collector current and the equivalent resistance;

[0024] A third calculation unit is used to calculate the on-state voltage drop difference of the IGBT device in the monitoring period;

[0025] The analysis unit is used to calculate the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference, and determine the aging condition of the IGBT device according to the relative thermal resistance.

[0026] Optionally, the calculating the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference includes:

[0027] Substituting the calculation coefficient, the device loss and the on-state voltage drop difference into a relative thermal resistance calculation formula to calculate the relative thermal resistance of the IGBT device;

[0028] Wherein, the relative thermal resistance calculation formula is:

[0029] ;

[0030] In the formula, is the relative thermal resistance, is the calculation coefficient, The device loss, is the conduction voltage drop difference.

[0031] Optionally, the first computing unit is specifically configured to:

[0032] Obtain the device parameter table of the IGBT device from the IGBT device manufacturer;

[0033] Obtaining a junction temperature-saturation voltage drop curve and an equivalent resistance of the IGBT device based on the device parameter table;

[0034] The calculation coefficient is determined according to the junction temperature-saturation voltage drop curve.

[0035] Optionally, determining the aging condition of the IGBT device according to the relative thermal resistance includes:

[0036] The variation trend of the relative thermal resistance is determined according to the relative thermal resistance of a plurality of cycles to be detected, thereby determining the aging condition of the IGBT device according to the variation trend.

[0037] A third aspect of the present invention provides a modular multi-level converter IGBT aging monitoring device, the device comprising a processor and a memory:

[0038] The memory is used to store program code and transmit the program code to the processor;

[0039] The processor is used to execute the steps of the modular multi-level converter IGBT aging monitoring method as described in the first aspect according to the instructions in the program code.

[0040] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program codes, and the program codes are used to execute the modular multi-level converter IGBT aging monitoring method described in the first aspect.

[0041] It can be seen from the above technical solutions that the present invention has the following advantages:

[0042] The present invention provides a modular multi-level converter IGBT aging monitoring method. The device aging status is evaluated based on the device thermal resistance, and it is not necessary to accurately calculate the absolute value of the thermal resistance at each moment. It is only necessary to pay attention to the change value of the device thermal resistance (i.e., the relative thermal resistance) after the system has been running for a period of time to reflect the relative degree of device aging. Therefore, the present invention derives a relative thermal resistance calculation method based on the device thermal resistance of the IGBT device, and calculates the relative thermal resistance of the IGBT device according to the relevant parameters of the IGBT device, so as to judge the aging degree of the IGBT according to the relative thermal resistance of the IGBT device. The method of the present invention is simple to implement and can quickly monitor all devices. Thus, the problem that the existing method is complex to implement and difficult to quickly monitor the aging of the IGBT is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 A schematic diagram of a flow chart of a modular multi-level converter IGBT aging monitoring method provided by an embodiment of the present invention;

[0045] Figure 2 A schematic structural diagram of a modular multi-level converter IGBT aging monitoring system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that evaluating the aging status of a device based on the device thermal resistance does not require accurate calculation of the absolute value of the thermal resistance at each moment. It is only necessary to pay attention to the change in the device thermal resistance (i.e., the relative thermal resistance) after the system has been running for a period of time to reflect the relative degree of device aging. Therefore, the present invention proposes a modular multi-level converter IGBT aging monitoring method based on the relative thermal resistance of the device. The monitoring method of the present invention is simple to implement and can simultaneously evaluate the aging status of all devices in the MMC.

[0048] The following is an explanation of the derivation process of the relative thermal resistance calculation of the present invention:

[0049] The thermal resistance of IGBT device can be expressed as formula (1), where P loss is the device loss, T j is the device junction temperature, T c is the device case temperature.

[0050] (1)

[0051] Since the device loss is related to the current flowing through the device and the device equivalent resistance, the effect of thermal resistance change on P can be ignored within a monitoring cycle. loss The device case temperature is determined by the heat dissipation system. When the MMC is running stably, the device case temperature generally remains unchanged within a monitoring cycle. Therefore, the relative thermal resistance after the system runs for a monitoring cycle is It can be expressed as

[0052] (2)

[0053] in is the junction temperature difference of the device before and after a monitoring cycle. From formula (2), it can be seen that in order to monitor the relative thermal resistance of the device online, it is necessary to obtain the junction temperature difference and loss of the device before and after a monitoring cycle.

[0054] The collector current I C Given, the junction temperature T j and saturation conduction voltage drop V CE,satThere is a linear relationship, as shown in formula (3), where the coefficients α and β can be obtained based on the junction temperature-saturation voltage drop curve provided by the device manufacturer. The device loss is proportional to the product of the square of the collector current and the device equivalent resistance. The device equivalent resistance can also be obtained from the device parameter table provided by the manufacturer.

[0055] (3)

[0056] Therefore, when the MMC operating power remains unchanged during a monitoring cycle, that is, the collector current is approximately unchanged, the relative thermal resistance of the device It can be simplified as shown in formula (4). This conclusion shows that the on-state voltage drop difference before and after a monitoring cycle can be compared ( ) to reflect the relative thermal resistance of the device, and thus reflect the degree of device aging.

[0057] (4)

[0058] See also Figure 1 , a modular multi-level converter IGBT aging monitoring method provided in an embodiment of the present invention comprises:

[0059] Step 101: Determine the equivalent resistance and calculation coefficient of the IGBT device.

[0060] In one embodiment, step 101 includes:

[0061] Obtain a device parameter table of the IGBT device from the IGBT device manufacturer; obtain a junction temperature-saturation voltage drop curve and an equivalent resistance of the IGBT device based on the device parameter table; and determine a calculation coefficient based on the junction temperature-saturation voltage drop curve.

[0062] It should be noted that the calculation coefficients α and β can be obtained based on the junction temperature-saturation voltage drop curve provided by the device manufacturer.

[0063] Step 102: determine the collector current of the IGBT device when the system where the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device based on the collector current and the equivalent resistance.

[0064] It should be noted that the device loss is proportional to the product of the square of the collector current and the device equivalent resistance.

[0065] Step 103: Calculate the on-state voltage drop difference of the IGBT device during the monitoring period.

[0066] It should be noted that the on-state voltage drop difference of the IGBT device during the monitoring period is calculated by monitoring the on-state voltage drop after the monitoring period.

[0067] Step 104 : Calculate the relative thermal resistance of the IGBT device according to the calculation coefficient, device loss and on-state voltage drop difference, and determine the aging condition of the IGBT device according to the relative thermal resistance.

[0068] In one embodiment, step 104 includes:

[0069] The calculation coefficient, device loss and on-state voltage drop difference are substituted into the relative thermal resistance calculation formula to calculate the relative thermal resistance of the IGBT device; the change trend of the relative thermal resistance is determined according to the relative thermal resistance of multiple cycles to be tested, and the aging of the IGBT device is determined according to the change trend.

[0070] Among them, the relative thermal resistance calculation formula is:

[0071] ;

[0072] In the formula, is the relative thermal resistance, To calculate the coefficient, Device loss, is the conduction voltage drop difference.

[0073] A modular multi-level converter IGBT aging monitoring method provided in an embodiment of the present invention evaluates the device aging status based on the device thermal resistance, and does not need to accurately calculate the absolute value of the thermal resistance at each moment. It only needs to pay attention to the change value of the device thermal resistance (i.e., relative thermal resistance) after the system has been running for a period of time to reflect the relative degree of device aging; therefore, the present invention derives a relative thermal resistance calculation method based on the device thermal resistance of the IGBT device, and calculates the relative thermal resistance of the IGBT device according to the relevant parameters of the IGBT device, so as to judge the degree of IGBT aging according to the relative thermal resistance of the IGBT device. The method of this embodiment is simple to implement and can quickly monitor all devices. This solves the problem that the existing method is complex to implement and difficult to quickly monitor the aging of the IGBT.

[0074] The above is a modular multi-level converter IGBT aging monitoring method provided in an embodiment of the present invention. The following is a modular multi-level converter IGBT aging monitoring system provided in an embodiment of the present invention.

[0075] See also Figure 2 , a modular multi-level converter IGBT aging monitoring system provided in an embodiment of the present invention includes:

[0076] The first calculation unit 201 is used to determine the equivalent resistance of the IGBT device and the calculation coefficient.

[0077] The second calculation unit 202 is used to determine the collector current of the IGBT device when the system where the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device according to the collector current and the equivalent resistance.

[0078] The third calculation unit 203 is used to calculate the on-state voltage drop difference of the IGBT device in the monitoring period.

[0079] The analysis unit 204 is used to calculate the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference, and determine the aging condition of the IGBT device according to the relative thermal resistance.

[0080] A modular multi-level converter IGBT aging monitoring system provided in an embodiment of the present invention evaluates the aging status of the device based on the device thermal resistance, and does not need to accurately calculate the absolute value of the thermal resistance at each moment. It only needs to pay attention to the change value of the device thermal resistance (i.e., the relative thermal resistance) after the system has been running for a period of time to reflect the relative degree of device aging; therefore, the present invention derives a relative thermal resistance calculation method based on the device thermal resistance of the IGBT device, and calculates the relative thermal resistance of the IGBT device according to the relevant parameters of the IGBT device, so as to judge the aging degree of the IGBT according to the relative thermal resistance of the IGBT device. The system of this embodiment is simple to implement and can quickly monitor all devices. This solves the problem that the existing method is complex to implement and difficult to quickly monitor the aging of the IGBT.

[0081] Furthermore, an embodiment of the present invention also provides a modular multi-level converter IGBT aging monitoring device, the device comprising a processor and a memory:

[0082] The memory is used to store program code and transmit the program code to the processor;

[0083] The processor is used to execute the steps of the modular multi-level converter IGBT aging monitoring method as described in the above method embodiment according to the instructions in the program code.

[0084] Furthermore, an embodiment of the present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium is used to store program codes, and the program codes are used to execute the modular multi-level converter IGBT aging monitoring method described in the above method embodiment.

[0085] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0086] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0087] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0089] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0090] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modular multi-level converter IGBT aging monitoring method, characterized in that: include: Determine the equivalent resistance of the IGBT device and the calculation coefficient; Determine the collector current of the IGBT device when the system in which the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device according to the collector current and the equivalent resistance; Calculate the on-state voltage drop difference of the IGBT device during the monitoring cycle; The relative thermal resistance of the IGBT device is calculated according to the calculation coefficient, the device loss and the on-state voltage drop difference, and the aging condition of the IGBT device is determined according to the relative thermal resistance.

2. The modular multilevel converter IGBT aging monitoring method according to claim 1, characterized in that: The step of calculating the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference comprises: Substituting the calculation coefficient, the device loss and the on-state voltage drop difference into a relative thermal resistance calculation formula to calculate the relative thermal resistance of the IGBT device; Wherein, the relative thermal resistance calculation formula is: ； In the formula, is the relative thermal resistance, is the calculation coefficient, The device loss, is the conduction voltage drop difference, I C is the collector current of the IGBT device.

3. The modular multilevel converter IGBT aging monitoring method according to claim 1, characterized in that: The determining of the equivalent resistance of the IGBT device and the calculation coefficient comprises: Obtain the device parameter table of the IGBT device from the IGBT device manufacturer; Obtaining a junction temperature-saturation voltage drop curve and an equivalent resistance of the IGBT device based on the device parameter table; The calculation coefficient is determined according to the junction temperature-saturation voltage drop curve.

4. The modular multilevel converter IGBT aging monitoring method according to claim 1, characterized in that: Determining the aging condition of the IGBT device according to the relative thermal resistance includes: The variation trend of the relative thermal resistance is determined according to the relative thermal resistance of a plurality of cycles to be detected, thereby determining the aging condition of the IGBT device according to the variation trend.

5. A modular multi-level converter IGBT aging monitoring system, characterized in that: include: A first calculation unit, used to determine an equivalent resistance of an IGBT device and a calculation coefficient; A second calculation unit is used to determine the collector current of the IGBT device when the system in which the IGBT device is located is in stable operation, and calculate the device loss of the IGBT device according to the collector current and the equivalent resistance; A third calculation unit is used to calculate the on-state voltage drop difference of the IGBT device in the monitoring period; The analysis unit is used to calculate the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference, and determine the aging condition of the IGBT device according to the relative thermal resistance.

6. The modular multilevel converter IGBT aging monitoring system according to claim 5, characterized in that: The step of calculating the relative thermal resistance of the IGBT device according to the calculation coefficient, the device loss and the on-state voltage drop difference comprises: Substituting the calculation coefficient, the device loss and the on-state voltage drop difference into a relative thermal resistance calculation formula to calculate the relative thermal resistance of the IGBT device; Wherein, the relative thermal resistance calculation formula is: ； In the formula, is the relative thermal resistance, is the calculation coefficient, The device loss, is the conduction voltage drop difference, I C is the collector current of the IGBT device.

7. The modular multilevel converter IGBT aging monitoring system according to claim 5, characterized in that: The first computing unit is specifically configured to: Obtain the device parameter table of the IGBT device from the IGBT device manufacturer; Obtaining a junction temperature-saturation voltage drop curve and an equivalent resistance of the IGBT device based on the device parameter table; The calculation coefficient is determined according to the junction temperature-saturation voltage drop curve.

8. The modular multilevel converter IGBT aging monitoring system according to claim 5, characterized in that: Determining the aging condition of the IGBT device according to the relative thermal resistance includes: The variation trend of the relative thermal resistance is determined according to the relative thermal resistance of a plurality of cycles to be detected, thereby determining the aging condition of the IGBT device according to the variation trend.

9. A modular multi-level converter IGBT aging monitoring device, characterized in that: The device comprises a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the modular multilevel converter IGBT aging monitoring method according to any one of claims 1 to 4 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium is used to store program codes, and the program codes are used to execute the modular multi-level converter IGBT aging monitoring method according to any one of claims 1 to 4.

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