Method, device, storage medium and electronic device for determining the junction temperature of a turn-off thyristor

Abstract

The present application provides a method, a device, a storage medium and an electronic device for determining the junction temperature of a gate turn-off thyristor. The method includes: determining a predetermined relationship characterizing the relationship among the storage time, the operating current and the operating junction temperature of the gate turn-off thyristor, where the storage time is the duration during the turn-off process when the gate turn-off thyristor is delayed in turn-off due to the internal carrier storage effect of the gate turn-off thyristor, and the operating current is the current flowing through the gate turn-off thyristor before the gate turn-off thyristor is actively turned off; obtaining the actual storage time and the actual operating current of the gate turn-off thyristor, where the actual storage time is the actual storage time and the actual operating current is the actual operating current; and determining the actual operating junction temperature of the gate turn-off thyristor according to the actual storage time, the actual operating current and the predetermined relationship. The present application at least solves the problem in the prior art that the junction temperature measurement of the gate turn-off thyristor device is inaccurate, threatening the safe and stable operation of the system and equipment.

Description

Technical Field

[0001] The present application relates to the technical field of electronic power device detection. Specifically, it relates to a method, device, computer-readable storage medium, and electronic device for determining the operating junction temperature of a gate turn-off thyristor. Background Technique

[0002] The gate turn-off thyristor device has the advantages of low conduction loss and high reliability, and is suitable for high-voltage and high-power application scenarios such as converters for high-voltage direct current transmission. In such application scenarios, the state of the gate turn-off thyristor device will directly affect the safe and stable operation of the system. Existing research shows that 31% of the faults in converters are caused by the failure of power semiconductor devices, and 60% of the failures of power semiconductor devices are related to the junction temperature.

[0003] However, in the prior art, there is a problem that the junction temperature measurement of the gate turn-off thyristor device is inaccurate, which threatens the safe and stable operation of the system and equipment. Summary of the Invention

[0004] The main purpose of the present application is to provide a method, device, computer-readable storage medium, and electronic device for determining the operating junction temperature of a gate turn-off thyristor, so as to at least solve the problem that the junction temperature measurement of the gate turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0005] Based on the above purpose, according to one aspect of the present application, a method for determining the operating junction temperature of a gate turn-off thyristor is provided, including: determining a predetermined relationship characterizing the relationship between the storage time, operating current, and operating junction temperature of the gate turn-off thyristor, where the storage time is the duration during the turn-off process when the gate turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the gate turn-off thyristor, and the operating current is the current flowing through the gate turn-off thyristor before the gate turn-off thyristor actively turns off; obtaining the actual storage time and actual operating current of the gate turn-off thyristor, where the actual storage time is the actual storage time and the actual operating current is the actual operating current; and determining the actual operating junction temperature of the gate turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0006] Optionally, determining a predetermined relationship characterizing the relationship between the storage time, operating current, and operating junction temperature of the gate turn-off thyristor includes: obtaining the operating current of the gate turn-off thyristor at different operating junction temperatures and the voltage waveforms of the anode and cathode of the gate turn-off thyristor; determining the storage time at different operating junction temperatures according to the voltage waveforms to obtain a data set including multiple operating junction temperatures, corresponding multiple operating currents, and corresponding multiple storage times; and determining the predetermined relationship according to the data set.

[0007] Optionally, determining the storage time at different working junction temperatures according to the voltage waveform includes: determining, according to the voltage waveform, the moment when the voltage between the anode and cathode in the voltage waveform is less than the voltage threshold as the start moment of the storage time; determining, according to the voltage waveform, the moment when the voltage change rate between the anode and cathode in the voltage waveform is greater than a predetermined threshold as the end moment of the storage time; and determining the storage time at different working junction temperatures as the difference between the end moment and the start moment according to the start moment and the end moment at different working junction temperatures.

[0008] Optionally, obtaining the working current of the turn-off thyristor at different working junction temperatures and the voltage waveform between the anode and cathode of the turn-off thyristor includes: heating the turn-off thyristor to multiple working junction temperatures by a double-sided heating method; performing an active turn-off experiment on the turn-off thyristor at multiple working junction temperatures based on a double-pulse circuit, and measuring the change of the voltage between the anode and cathode with time in the active turn-off experiment to obtain the voltage waveform; and measuring the working current of the turn-off thyristor in multiple active turn-off experiments through a Rogowski coil.

[0009] Optionally, determining the predetermined relationship according to the data set includes one of the following: performing data fitting on the data in the data set to obtain a function representing the predetermined relationship; establishing a machine learning model, and training the machine learning model based on the data set to obtain a target model representing the predetermined relationship.

[0010] Optionally, after determining the actual working junction temperature of the turn-off thyristor according to the actual storage time, the actual working current, and the predetermined relationship, the method further includes at least one of the following: determining the operating state of the turn-off thyristor according to the actual working junction temperature, determining that the operating state is normal when the actual working junction temperature is within a preset junction temperature range, and determining that the operating state is abnormal when the actual working junction temperature is not within the preset junction temperature range; determining the actual thermal resistance of the turn-off thyristor according to the actual working junction temperature, and determining the aging degree of the turn-off thyristor according to the actual thermal resistance.

[0011] Optionally, the modular multilevel converter includes a plurality of MMC sub-modules, and the MMC sub-modules include the turn-off thyristors. After determining the actual operating junction temperature of the turn-off thyristors according to the actual storage time, the actual operating current, and the predetermined relationship, the method further includes: determining the switching priority of the turn-off thyristors according to the actual operating junction temperatures of the plurality of turn-off thyristors, wherein the greater the actual operating junction temperature, the smaller the corresponding switching priority; and controlling the switching states of the plurality of thyristors according to the switching priorities of the plurality of thyristors to adjust the charge and discharge processes of the plurality of MMC sub-modules.

[0012] According to another aspect of the present application, there is provided a device for determining the operating junction temperature of a turn-off thyristor, including: a first determination unit configured to determine a predetermined relationship characterizing the relationship between the storage time, the operating current, and the operating junction temperature of the turn-off thyristor, where the storage time is the duration during which the turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the turn-off thyristor during the turn-off process, and the operating current is the current flowing through the turn-off thyristor before the turn-off thyristor actively turns off; an acquisition unit configured to acquire the actual storage time and the actual operating current of the turn-off thyristor, where the actual storage time is the actual storage time, and the actual operating current is the actual operating current; and a second determination unit configured to determine the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0013] According to still another aspect of the present application, there is provided a computer-readable storage medium, where the computer-readable storage medium includes a stored program, and when the program runs, it controls the device where the computer-readable storage medium is located to execute any one of the above methods.

[0014] According to yet another aspect of the present application, there is further provided an electronic device, including: one or more processors, a memory, and one or more programs, where the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include those for executing any one of the above methods.

[0015] Applying the technical solution of the present application, taking the duration of the storage stage (i.e., the storage time) during the active turn-off process of the turn-off thyristor device as the temperature-sensitive electrical parameter, establishing a quantitative relationship among the storage time, operating current, and operating junction temperature of the turn-off thyristor, and determining the actual operating junction temperature of the device according to this quantitative relationship and the actual storage time and actual operating current of the device. Since the storage time is sensitive to the change in junction temperature, the sensitivity of the on-line monitoring of the device junction temperature is ensured. At the same time, since the storage time is not affected by the DC bus voltage, the interference of the DC bus voltage fluctuation on the device junction temperature is avoided, and the accuracy of the on-line monitoring of the device junction temperature is ensured, solving the problem that the measurement of the junction temperature of the turn-off thyristor device in the prior art is inaccurate and threatening the safe and stable operation of the system and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specification drawings forming a part of the present application are used to provide a further understanding of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0017] Figure 1 It shows a hardware structure block diagram of a mobile terminal for implementing a method for determining the operating junction temperature of a turn-off thyristor provided in an embodiment of the present application;

[0018] Figure 2 It shows a schematic flowchart of a method for determining the operating junction temperature of a turn-off thyristor provided in an embodiment of the present application;

[0019] Figure 3 It shows a schematic diagram of the trend of each electrical parameter of a turn-off thyristor over time during the active turn-off process provided in an embodiment of the present application;

[0020] Figure 4 It shows a schematic diagram of the voltage waveform of a turn-off thyristor during the active turn-off process provided in an embodiment of the present application;

[0021] Figure 5 It shows a schematic diagram of the voltage waveform of a turn-off thyristor during the active turn-off process at different junction temperatures provided in an embodiment of the present application;

[0022] Figure 6 It shows a flowchart for determining the operating junction temperature of a turn-off thyristor provided in an embodiment of the present application;

[0023] Figure 7 It shows a structure block diagram of a device for determining the operating junction temperature of a turn-off thyristor provided in an embodiment of the present application.

[0024] Among them, the drawings include the following reference numerals:

[0025] 102. Processor; 104. Memory; 106. Transmission device; 108. Input / output device. Detailed implementation manners

[0026] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0028] It should be noted that the terms "first", "second", etc. in the description and claims of the present application and the accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data may be interchanged under appropriate circumstances for the embodiments of the present application described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] Currently, the junction temperature of a turn-off thyristor device is monitored through the on-state gate-cathode voltage, but the sensitivity of this parameter is relatively low under large load currents. Compared with static temperature-sensitive electrical parameters such as on-state voltage drop, the dynamic temperature-sensitive electrical parameters during the switching transient process have higher sensitivity, but are easily affected by the DC bus voltage fluctuation. In application scenarios such as MMC-HVDC (Modular Multilevel Converter-High Voltage Direct Current), there are fluctuations in the DC capacitor voltage, which will affect the dynamic temperature-sensitive electrical parameters of the device and interfere with the measurement results of the junction temperature.

[0030] Therefore, in the prior art, there is a problem that the measurement of the junction temperature of a turn-off thyristor device is inaccurate, threatening the safe and stable operation of the system and equipment. To solve the above technical problems, the embodiments of the present application provide a method, device, computer-readable storage medium, and electronic device for determining the operating junction temperature of a turn-off thyristor.

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] The method embodiments provided in the embodiments of the present application can be executed on a mobile terminal, a computer terminal, or a similar computing device. Taking the operation on a mobile terminal as an example, Figure 1 is a hardware structure block diagram of a mobile terminal for determining the operating junction temperature of a thyristor that can be turned off according to an embodiment of the present invention. As Figure 1 shown, the mobile terminal may include one or more ( Figure 1 only one is shown in the figure) processors 102 (the processor 102 may include, but is not limited to, a processing device such as a microprocessor MCU or a field programmable gate array FPGA) and a memory 104 for storing data. Among them, the mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those of ordinary skill in the art can understand that Figure 1 the structure shown is only schematic and does not limit the structure of the mobile terminal. For example, the mobile terminal may further include more or fewer components than Figure 1 shown in the figure, or have a different configuration from Figure 1 shown in the figure.

[0033] The memory 104 can be used to store computer programs. For example, software programs and modules of application software, such as the computer program corresponding to the display method of device information in the embodiments of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, implements the described method. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some instances, the memory 104 may further include a memory remotely disposed relative to the processor 102, and these remote memories can be connected to the mobile terminal through a network. Examples of the network include, but are not limited to, the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the network may include a wireless network provided by a communication provider of the mobile terminal. In one instance, the transmission device 106 includes a network adapter (abbreviated as NIC), which can be connected to other network devices through a base station and thus can communicate with the Internet. In one instance, the transmission device 106 may be a radio frequency (abbreviated as RF) module, which is used to communicate with the Internet wirelessly.

[0034] In this embodiment, a method for determining the operating junction temperature of a gate turn-off thyristor operating on a mobile terminal, a computer terminal, or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. And although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0035] Figure 2 It is a flowchart of a method for determining the operating junction temperature of a gate turn-off thyristor according to an embodiment of the present application. As Figure 2 shown, the method includes the following steps:

[0036] Step S201, determine a predetermined relationship characterizing the relationship between the storage time, operating current, and operating junction temperature of the gate turn-off thyristor. The storage time is the duration during the turn-off process in which the gate turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the gate turn-off thyristor, and the operating current is the current flowing through the gate turn-off thyristor before the gate turn-off thyristor actively turns off;

[0037] Specifically, the storage time is the duration of the storage stage during the active turn-off process of the gate turn-off thyristor. During the active turn-off process, there is a time delay that cannot be immediately turned off due to the internal carrier storage effect. During the storage time, although the device has received a turn-off command, there are still a large number of stored carriers inside the device, and the existence of these carriers causes the device to continue to maintain the on state.

[0038] Step S202, obtain the actual storage time and actual operating current of the gate turn-off thyristor. The actual storage time is the actual storage time, and the actual operating current is the actual operating current;

[0039] Step S203, determine the actual operating junction temperature of the gate turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0040] Specifically, according to this predetermined relationship, determine the operating junction temperature corresponding to the actual storage time and actual operating current as the actual operating junction temperature.

[0041] In this embodiment, first, a predetermined relationship characterizing the storage time, the operating current before turn-off, and the operating junction temperature of the turn-off thyristor during the turn-off process is determined; then, the actual storage time and the actual operating current of the turn-off thyristor are obtained; finally, the actual operating junction temperature of the turn-off thyristor is determined according to the predetermined relationship, the actual storage time, and the actual operating current. In this application, the duration of the storage stage (i.e., the storage time) of the turn-off thyristor device during the active turn-off process is used as the temperature-sensitive electrical parameter to establish a quantitative relationship among the storage time, the operating current, and the operating junction temperature of the turn-off thyristor. According to this quantitative relationship and the actual storage time and actual operating current of the device, the actual operating junction temperature of the device is determined. Since the storage time is sensitive to the change in the junction temperature, the sensitivity of the on-line monitoring of the device junction temperature is ensured. At the same time, since the storage time is not affected by the DC bus voltage, the interference of the DC bus voltage fluctuation on the device junction temperature is avoided, and the accuracy of the on-line monitoring of the device junction temperature is ensured, solving the problem that the junction temperature measurement of the turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0042] Specifically, at the end of the storage stage of the turn-off thyristor device, the device space charge region just begins to expand, the device current is basically equal to the current before turn-off, that is, the device current has not decreased yet, and the anode-cathode voltage of the device is much lower than the DC bus voltage. Therefore, the fluctuation of the DC bus voltage will not affect the storage time.

[0043] The temperature-sensitive electrical parameter method can realize the non-invasive measurement of the junction temperature by calibrating the mapping relationship between the device junction temperature and the electrical quantity, taking the chip itself as the temperature sensor, and has the advantage of fast response speed. It is the most promising on-line measurement method for the junction temperature.

[0044] For the turn-off thyristor device, too high a junction temperature will cause the blocking state leakage current index of the chip to rise, further increasing the power loss and ultimately triggering the intrinsic thermal breakdown failure of the chip. In this application, the storage time of the turn-off thyristor device during the active turn-off process is used as the temperature-sensitive electrical parameter. Through the temperature-sensitive electrical parameter method, the problem that the dynamic temperature-sensitive electrical parameter is easily affected by the DC bus voltage can be solved, the junction temperature during the device operation can be accurately measured, the active thermal management of the device can be realized to suppress too high a junction temperature, and the reliability of the device and the converter can be evaluated through state monitoring, which helps to ensure the safe and stable operation of the equipment and the system.

[0045] It should be noted that the turn-off thyristor mentioned in this application refers to the turn-off thyristor device that meets the "hard drive" condition. Among them, the definition of hard drive is that the device completes the turn-off under the unit gain with a turn-off gain of 1. The turn-off thyristor in this application includes the integrated gate-commutated thyristor (In Gate Turn-Off Thyristor (GTO), Insulated Gate Commutated Thyristor (IGCT for short), MOS Turn-Off Thyristor (MTO for short), Emitter Turn-Off Thyristor (ETO for short), or Integrated Emitter Turn-Off Thyristor (IETO for short), etc.

[0046] In an alternative solution, determining a predetermined relationship characterizing the relationship among the storage time, operating current, and operating junction temperature of the Gate Turn-Off Thyristor includes: obtaining the operating current of the Gate Turn-Off Thyristor at different operating junction temperatures and the voltage waveform of the anode and cathode of the Gate Turn-Off Thyristor; determining the storage time at different operating junction temperatures according to the voltage waveform, obtaining a data set including a plurality of the operating junction temperatures, corresponding plurality of the operating currents, and corresponding plurality of the storage times; and determining the predetermined relationship according to the data set. In this embodiment, obtaining the operating current before turn-off and the anode-cathode voltage waveform corresponding to multiple device junction temperatures, then determining the storage time corresponding to multiple device junction temperatures according to the anode-cathode voltage waveform, obtaining a data set including multiple junction temperatures, the operating current corresponding to each junction temperature, and the storage time, and obtaining a predetermined relationship that can accurately characterize the quantitative relationship among the storage time, operating current, and operating junction temperature according to this data set, further ensuring that the actual junction temperature of the Gate Turn-Off Thyristor determined according to this predetermined relationship is relatively accurate.

[0047] Among them, the voltage waveform reflects the change of the voltage of the anode and cathode of the Gate Turn-Off Thyristor over time. The voltage of the anode and cathode refers to the voltage drop between the anode and cathode of the Gate Turn-Off Thyristor.

[0048] In some embodiments, determining the storage time at different operating junction temperatures according to the voltage waveform includes: determining, according to the voltage waveform, the moment when the voltage between the anode and cathode in the voltage waveform is less than the voltage threshold as the starting moment of the storage time; determining, according to the voltage waveform, the moment when the voltage change rate between the anode and cathode in the voltage waveform is greater than the predetermined threshold as the ending moment of the storage time; and determining the storage time at different operating junction temperatures as the difference between the ending moment and the starting moment according to the starting moment and the ending moment at different operating junction temperatures. In this embodiment, the moment when the anode-cathode voltage is lower than the voltage threshold is used as the starting moment of the storage time, and the moment when the voltage change rate of the anode-cathode voltage is higher than the predetermined threshold is used as the ending moment of the storage time. By accurately determining the starting moment and the ending moment of the storage time, the storage time can be measured more precisely, which is crucial for establishing the predetermined relationship and determining the actual operating junction temperature.

[0049] The starting point (i.e., the starting moment) of the storage stage of the turn-off thyristor is the moment when the commutation of the turn-off thyristor device is completed. When the commutation stage ends, the anode current is all switched to the gate, a space charge region is established in the PN junction of the device, and the gate-cathode voltage drops, causing the anode-cathode voltage of the device to drop. Therefore, it can be determined that the moment when the anode-cathode voltage is lower than the voltage threshold is the moment when the commutation is completed, i.e., the starting point of the storage stage. The end point (i.e., the ending moment) of the storage stage of the turn-off thyristor is the moment when the space charge region of the device just begins to expand and the anode voltage is rapidly established. When the storage stage ends, a space charge region begins to be established at another PN junction in the device, and the anode-cathode voltage of the device will rise rapidly. Therefore, it can be determined that the moment when the rising rate of the anode-cathode voltage is higher than the predetermined threshold is the end point of the storage stage.

[0050] Among them, the setting of the voltage threshold and the predetermined threshold can be obtained by performing a double-pulse test on the turn-off thyristor. Reasonably setting the voltage threshold and the predetermined threshold can further ensure the accuracy and effectiveness of the monitoring.

[0051] Taking the turn-off thyristor as an IGCT as an example, Figure 3 shows the anode-cathode voltage drop , anode current and cathode current and other electrical parameter trend diagrams over time during the active turn-off process of the turn-off thyristor. Figure 3 In it, the abscissa is the time t (unit: μs), and the ordinate includes the anode-cathode voltage drop (unit: V), anode current (unit: A), and cathode current (unit: A); Figure 4 shows the voltage waveform diagram of the anode-cathode voltage drop during the active turn-off process of the turn-off thyristor. Figure 4In it, the abscissa is time (unit: μs), and the ordinate is the anode-cathode voltage drop (unit: V).

[0052] As Figure 3 and Figure 4 shown, during the turn-off process of the IGCT device, the starting point of its storage stage is the moment when the commutation of the IGCT device is completed, and the ending point is the moment when the space charge region of the device begins to expand and the anode voltage is rapidly established. For the criterion of the starting point of the storage stage, it satisfies: , where is the anode-cathode voltage drop of the IGCT device at time , and is the voltage threshold. When the commutation stage ends, all the anode current of the IGCT device is transferred to the gate, and a space charge region is established in the junction of the IGCT device, and the gate-cathode voltage drops, resulting in a decrease in the anode-cathode voltage of the device. Therefore, the moment when the anode-cathode voltage is lower than the threshold can be considered as the moment when the commutation is completed, that is, the starting point of the storage stage. During the turn-off process of the IGCT device, the judgment of the ending point of its storage stage satisfies: , where is the rising rate of the anode-cathode voltage of the IGCT device at time , and is the set voltage rising rate threshold, that is, the aforementioned predetermined threshold. When the storage stage ends, a space charge region begins to be established at the junction, and the anode-cathode voltage of the device will rise rapidly. Therefore, the moment when the rising rate of the anode-cathode voltage is higher than the threshold can be considered as the ending point of the storage stage. Then, the storage time

[0053] Figure 5 . At the end of the storage stage, the space charge region has not yet expanded, and the anode-cathode voltage drop of the device is much lower than the DC bus voltage. Therefore, the fluctuation of the DC bus voltage will not affect the storage time. Figure 5 shows the anode-cathode voltage waveforms during the turn-off process of the IGCT device at different junction temperatures. Among them, the abscissa is time (unit: μs), and the ordinate is the anode-cathode voltage drop Figure 5 . As j shown, as the junction temperature T

[0054] increases, the time required for the IGCT device to rise from the completion of commutation to the anode-cathode voltage becomes longer, which proves that the storage time of the IGCT device is sensitive to the change of the junction temperature and can be used as a temperature-sensitive electrical parameter.Before determining the storage time at different working junction temperatures according to the voltage waveform, the method may further include: performing digital signal processing on the voltage waveform to remove noise and improve measurement accuracy. Determining the storage time at different working junction temperatures according to the voltage waveform includes: determining the storage time at different working junction temperatures according to the voltage waveform after digital signal processing.

[0055] The digital signal processing methods include filtering, smoothing, peak detection, etc., to improve the accuracy and robustness of the storage time measurement through these methods. An adaptive filter can be used to adjust the filtering parameters according to the real-time change of the voltage waveform to remove the waveform noise and improve the signal quality.

[0056] According to some other embodiments of the present application, obtaining the working current of the turn-off thyristor at different working junction temperatures and the voltage waveform of the anode and cathode of the turn-off thyristor includes: heating the turn-off thyristor to multiple working junction temperatures by a double-sided heating method; performing an active turn-off experiment on the turn-off thyristor at multiple working junction temperatures based on a double-pulse circuit and measuring the change of the voltage of the anode and cathode with time in the active turn-off experiment to obtain the voltage waveform; measuring the working current of the turn-off thyristor in multiple active turn-off experiments through a Rogowski coil. In this embodiment, the double-sided heating method can more evenly control the junction temperature of the device, providing a good experimental basis for establishing the predetermined relationship among the storage time, the working current, and the working junction temperature; the double-pulse circuit is selected for the device experiment circuit to ensure the controllability and repeatability of the experimental conditions. Conducting the device experiment in the double-pulse test circuit can simulate the working conditions of the device in actual applications, which is of great value for establishing the predetermined relationship applicable to the actual working conditions of the device; the measurement of the working current is carried out through a non-invasive Rogowski coil, which will not affect the normal operation of the device, can avoid interfering with the device, and ensure the accuracy of the current data at the same time. Through the above method, rich device data can be obtained, providing data support for the accurate establishment of the subsequent predetermined relationship.

[0057] Specifically, the heating sources of the double-sided heating method include but are not limited to ceramic heaters or infrared heating lamps, etc., to provide an accurate junction temperature control environment for facilitating data collection and the establishment of the predetermined relationship. The parameter adjustment of the double-pulse circuit includes but is not limited to: adjusting the pulse width and frequency to adapt to the operating state of the device at different working currents; controlling the pulse voltage to ensure that the device does not enter the overload state and can accurately measure the storage time.

[0058] In addition, the method for obtaining the actual storage time and the actual working current is the same as the method for obtaining the storage time and the working current. That is to say, to obtain the actual storage time of the turn-off thyristor, the voltage waveform of the anode-cathode of the turn-off thyristor can be obtained in real time, and then through a real-time data processing algorithm, the actual storage time can be obtained, ensuring that the measurement of the actual storage time can be carried out online and the response time meets the actual application requirements. The actual working current of the turn-off thyristor can be measured by a Rogowski coil.

[0059] Exemplarily, determining the predetermined relationship according to the data set includes one of the following: performing data fitting on the data in the data set to obtain a function representing the predetermined relationship; establishing a machine learning model and training the machine learning model based on the data set to obtain a target model representing the predetermined relationship. Obtaining a function representing the predetermined relationship by fitting the data in the data set can accurately describe the relationship between the operating junction temperature, the working current, and the storage time of the turn-off thyristor in the form of a mathematical expression, which is beneficial to the monitoring of the actual operating junction temperature of the device; the machine learning model has a powerful non-linear mapping ability and can capture complex potential relationships in the data, thereby quantifying the complex relationship between the operating junction temperature, the working current, and the storage time of the turn-off thyristor, which is beneficial to the monitoring of the actual operating junction temperature of the device.

[0060] Among them, the data fitting methods include but are not limited to polynomial fitting and exponential fitting, etc. The machine learning models include but are not limited to support vector machine models, neural network models, and deep network models, etc.

[0061] Of course, in addition to machine learning, other algorithms such as particle swarm optimization algorithm and genetic algorithm can also be used in this application to optimize the parameter selection in the data fitting process, so as to construct a more accurate mathematical model representing the relationship among the operating junction temperature, the working current, and the storage time.

[0062] In some other embodiments of the present application, after determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship, the method further includes at least one of the following: determining the operating state of the turn-off thyristor according to the actual operating junction temperature, determining that the operating state is normal when the actual operating junction temperature is within a preset junction temperature range, and determining that the operating state is abnormal when the actual operating junction temperature is not within the preset junction temperature range; determining the actual thermal resistance of the turn-off thyristor according to the actual operating junction temperature, and determining the aging degree of the turn-off thyristor according to the actual thermal resistance. By the actual operating junction temperature of the device, to determine the operating health state of the turn-off thyristor, and / or to determine the aging degree of the turn-off thyristor, which is beneficial to realizing the fault prevention and proactive maintenance of the device where the device is located or the system, and optimizing the operating stability of the device or the system.

[0063] When the actual junction temperature exceeds a preset safety threshold, trigger the active intervention of the thermal management system of the device, such as increasing the cooling efficiency of the radiator or adjusting the operating current of the device, to reduce the actual junction temperature of the device.

[0064] In other embodiments, the modular multilevel converter includes a plurality of MMC sub-modules, and the MMC sub-module includes the turn-off thyristor. After determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship, the method further includes: determining the switching priority of the turn-off thyristor according to the actual operating junction temperatures of the plurality of turn-off thyristors, the larger the actual operating junction temperature, the smaller the corresponding switching priority; controlling the switching states of the plurality of thyristors according to the switching priorities of the plurality of thyristors to adjust the charging and discharging processes of the plurality of MMC sub-modules. In this embodiment, according to the actual junction temperatures of the turn-off thyristors in the plurality of MMC sub-modules, to control the switching priorities of the plurality of turn-off thyristors, thereby controlling the charging and discharging sequence of the plurality of MMC sub-modules, which can ensure the capacitance voltage balance of each MMC sub-module, realize the energy balance of the converter, and ensure a longer service life of the converter.

[0065] Specifically, multiple MMC sub-modules with the same structure are connected in series or in parallel to form the converter. In addition to the turn-off thyristors, the MMC sub-module also includes components such as capacitors and diodes. By controlling the conduction and turn-off of the turn-off thyristors, the input and removal of the MMC sub-module can be achieved, thereby changing the output voltage of the converter. Common MMC sub-module topologies include Half-Bridge Sub-module (HBSM), Full-Bridge Sub-module (FBSM), etc. By controlling the number of input and removed sub-modules, output voltages of different levels can be synthesized. For example, in an MMC composed of half-bridge sub-modules, each sub-module can output two levels, 0 or the capacitor voltage. Through the combination of multiple sub-modules, output voltages of multiple levels can be obtained, making the output voltage waveform closer to a sine wave.

[0066] After obtaining the actual junction temperature, information interaction can be carried out with the control system of the converter to adjust the commutation strategy, so as to optimize the temperature distribution of the device and improve the operation efficiency and reliability of the converter.

[0067] In the actual application process, the dynamic characteristics of the device will change under different gate voltages. Therefore, a gate voltage compensation algorithm can be added to correct the predetermined relationship under different gate voltages of the device to ensure the accuracy of junction temperature measurement. For example, by introducing a voltage sensor, the actual gate voltage value of the turn-off thyristor is monitored in real time, and the coefficient in the predetermined relationship is adjusted according to this voltage value to achieve this.

[0068] In addition, the determination method of the voltage threshold can be: using a double-pulse test to simulate the dynamic behavior of the turn-off thyristor, analyzing the dynamic characteristics of the turn-off thyristor during the turn-off process, obtaining the voltage change characteristics of the turn-off thyristor during the storage stage, and determining the voltage threshold according to this voltage change characteristic.

[0069] In other embodiments, the determination method of the voltage threshold can also be: obtaining the anode-cathode voltage waveform, gate-cathode voltage waveform, and anode current waveform of the turn-off thyristor when it works under different operating currents and different operating junction temperatures; according to the above waveforms, statistically analyzing the distribution of the starting voltage of the storage stage of the turn-off thyristor under different working conditions; and determining the voltage threshold that meets the different working conditions of the turn-off thyristor according to this distribution. This threshold should usually be set within the range where the voltage drops at the beginning of the storage stage, and considering the influence of noise and voltage fluctuations, the robustness of the threshold is ensured.

[0070] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the implementation process of the method for determining the operating junction temperature of the turn-off thyristor of the present application will be described in detail below in conjunction with specific embodiments.

[0071] This embodiment relates to a specific method for determining the operating junction temperature of a turn-off thyristor. In this embodiment, the turn-off thyristor is taken as an IGCT as an example. As Figure 6 shown, the method for determining the operating junction temperature of the IGCT device includes the following steps:

[0072] Step S1: Adjust the operating junction temperature of the IGCT device by means of double-sided heating, and conduct an active turn-off experiment on the IGCT device at different junction temperatures and operating currents based on a double-pulse circuit;

[0073] Step S2: Measure the anode-cathode voltage waveform during the active turn-off process of the IGCT device at different operating junction temperatures and the operating current before turn-off;

[0074] Step S3: Extract the storage time of the IGCT device according to the anode-cathode voltage waveform, and a data set including multiple storage times, corresponding multiple operating junction temperatures, and corresponding multiple operating currents can be obtained;

[0075] Step S4: According to the data set, fit the quantitative relationship among the storage time, operating current, and operating junction temperature;

[0076] Step S5: Monitor the actual anode-cathode voltage of the IGCT device to obtain the actual storage time, and monitor the actual operating current of the IGCT device. According to the fitted quantitative relationship, actual storage time, and actual operating current, determine the actual operating junction temperature of the IGCT device, and realize the on-line monitoring of the device junction temperature.

[0077] The present application utilizes the characteristics that the storage time is relatively sensitive to the change of the junction temperature and is not affected by the fluctuation of the DC capacitor voltage to realize the non-invasive measurement of the junction temperature of the IGCT device. Specifically, by utilizing the characteristic that the storage time is sensitive to the change of the junction temperature, the sensitivity of the on-line monitoring of the junction temperature of the IGCT device is improved. By utilizing the property that the storage time is not affected by the DC bus voltage, the influence of the DC capacitor voltage fluctuation on the dynamic temperature-sensitive electrical parameters of the IGCT device is avoided, and the accuracy of the junction temperature monitoring is improved, which can provide key information for the active thermal management and health status monitoring of the device, and contribute to ensuring the safe and stable operation of the equipment and system.

[0078] The embodiment of the present application also provides a device for determining the operating junction temperature of a gate turn-off thyristor. It should be noted that the device for determining the operating junction temperature of a gate turn-off thyristor in the embodiment of the present application can be used to execute the method for determining the operating junction temperature of a gate turn-off thyristor provided in the embodiment of the present application. The device for implementing the above embodiment and the preferred implementation manner has been described and will not be repeated here. As used hereinafter, the term "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0079] The following introduces the device for determining the operating junction temperature of a gate turn-off thyristor provided in the embodiment of the present application.

[0080] Figure 7 is a schematic diagram of the device for determining the operating junction temperature of a gate turn-off thyristor according to the embodiment of the present application. As Figure 7 shown, the device includes:

[0081] A first determination unit 10, configured to determine a predetermined relationship characterizing the relationship among the storage time, operating current, and operating junction temperature of the gate turn-off thyristor, where the storage time is the duration during which the gate turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the gate turn-off thyristor during the turn-off process, and the operating current is the current flowing through the gate turn-off thyristor before the gate turn-off thyristor actively turns off;

[0082] Specifically, the storage time is the duration of the storage stage during the active turn-off process of the gate turn-off thyristor. During the active turn-off process, due to the internal carrier storage effect, there is a time delay in not being able to turn off immediately. During the storage time, although the device has received a turn-off command, there are still a large number of stored carriers inside the device, and the existence of these carriers causes the device to continue to remain in the conducting state.

[0083] An acquisition unit 20, configured to acquire the actual storage time and actual operating current of the gate turn-off thyristor, where the actual storage time is the actual storage time, and the actual operating current is the actual operating current;

[0084] A second determination unit 30, configured to determine the actual operating junction temperature of the gate turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0085] Specifically, according to this predetermined relationship, the operating junction temperature corresponding to the actual storage time and actual operating current is determined as the actual operating junction temperature.

[0086] In this embodiment, a first determination unit is used to determine a predetermined relationship among the storage time, the operating current before turn-off, and the operating junction temperature of the turn-off thyristor during the turn-off process; an acquisition unit is used to acquire the actual storage time and the actual operating current of the turn-off thyristor; and a second determination unit is used to determine the actual operating junction temperature of the turn-off thyristor according to the predetermined relationship, the actual storage time, and the actual operating current. In this application, the duration of the storage stage (i.e., the storage time) of the turn-off thyristor device during the active turn-off process is used as a temperature-sensitive electrical parameter to establish a quantitative relationship among the storage time, the operating current, and the operating junction temperature of the turn-off thyristor. According to this quantitative relationship, the actual storage time and the actual operating current of the device, the actual operating junction temperature of the device can be determined. Since the storage time is sensitive to the change of the junction temperature, the sensitivity of the on-line monitoring of the device junction temperature is ensured. At the same time, since the storage time is not affected by the DC bus voltage, the interference of the DC bus voltage fluctuation on the device junction temperature is avoided, and the accuracy of the on-line monitoring of the device junction temperature is ensured, solving the problem that the junction temperature measurement of the turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0087] Specifically, at the end of the storage stage of the turn-off thyristor device, the device space charge region has just started to expand, the device current is basically equal to the current before turn-off, that is, the device current has not decreased yet, and the anode-cathode voltage of the device is much lower than the DC bus voltage. Therefore, the fluctuation of the DC bus voltage will not affect the storage time.

[0088] The temperature-sensitive electrical parameter method can realize non-invasive measurement of the junction temperature by calibrating the mapping relationship between the device junction temperature and the electrical quantity, taking the chip itself as a temperature sensor, and has the advantage of fast response speed, which is the most promising on-line measurement method for junction temperature.

[0089] For the turn-off thyristor device, too high a junction temperature will cause the blocking state leakage current index of the chip to rise, further increasing the power loss and ultimately triggering the intrinsic thermal breakdown failure of the chip. In this application, the storage time of the turn-off thyristor device during the active turn-off process is used as a temperature-sensitive electrical parameter. Through the temperature-sensitive electrical parameter method, the problem that the dynamic temperature-sensitive electrical parameter is easily affected by the DC bus voltage can be solved, the junction temperature during the operation of the device can be accurately measured, the active thermal management of the device can be realized to suppress too high a junction temperature, and the reliability of the device and the converter can be evaluated through state monitoring, which helps to ensure the safe and stable operation of the equipment and the system.

[0090] It should be noted that the turn-off thyristor mentioned in this application refers to a turn-off thyristor device that meets the "hard drive" condition. Among them, the definition of hard drive is that the device completes the turn-off under the unit gain with a turn-off gain of 1. The turn-off thyristors in this application include IGCT, MTO, ETO, or IETO, etc.

[0091] In an alternative solution, the first determination unit includes: an acquisition module, configured to acquire the operating current of the turn-off thyristor at different operating junction temperatures and the voltage waveform of the anode and cathode of the turn-off thyristor; a first determination module, configured to determine the storage time at different operating junction temperatures according to the voltage waveform, so as to obtain a data set including a plurality of the operating junction temperatures, corresponding plurality of the operating currents, and corresponding plurality of the storage times; a second determination module, configured to determine the predetermined relationship according to the data set. In this embodiment, the operating current before turn-off and the anode-cathode voltage waveform corresponding to multiple device junction temperatures are acquired, and then the storage time corresponding to multiple device junction temperatures is determined according to the anode-cathode voltage waveform, so as to obtain a data set including multiple junction temperatures, the operating current corresponding to each junction temperature, and the storage time. According to this data set, a predetermined relationship that can accurately characterize the quantitative relationship among the storage time, the operating current, and the operating junction temperature is obtained, which further ensures that the actual junction temperature of the turn-off thyristor determined according to this predetermined relationship is relatively accurate.

[0092] Wherein, the voltage waveform reflects the change of the voltage of the anode and cathode of the turn-off thyristor over time. The voltage of the anode and cathode refers to the voltage drop between the anode and cathode of the turn-off thyristor.

[0093] In some embodiments, the first determination module includes: a first determination sub-module, configured to determine, according to the voltage waveform, that the moment when the voltage of the anode and cathode in the voltage waveform is less than the voltage threshold is the starting moment of the storage time; a second determination sub-module, configured to determine, according to the voltage waveform, that the moment when the voltage change rate of the anode and cathode in the voltage waveform is greater than the predetermined threshold is the ending moment of the storage time; a third determination sub-module, configured to determine, according to the starting moment and the ending moment at different operating junction temperatures, that the storage time at different operating junction temperatures is the difference between the ending moment and the starting moment. In this embodiment, the moment when the anode-cathode voltage is lower than the voltage threshold is used as the starting moment of the storage time, and the moment when the voltage change rate of the anode-cathode voltage is higher than the predetermined threshold is used as the ending moment of the storage time. By accurately determining the starting moment and the ending moment of the storage time, the storage time can be measured more precisely, which is crucial for the establishment of the predetermined relationship and the determination of the actual operating junction temperature.

[0094] The starting point (i.e., the starting moment) of the storage stage of the gate turn-off thyristor is the moment when the commutation of the gate turn-off thyristor device is completed. When the commutation stage ends, the anode current is all transferred to the gate, a space charge region is established in the PN junction of the device, the gate-cathode voltage drops, causing the anode-cathode voltage of the device to drop. Therefore, it can be determined that the moment when the anode-cathode voltage is lower than the voltage threshold is the moment when the commutation is completed, i.e., the starting point of the storage stage. The ending point (i.e., the ending moment) of the storage stage of the gate turn-off thyristor is the moment when the space charge region of the device just begins to expand and the anode voltage is rapidly established. When the storage stage ends, a space charge region begins to be established at another PN junction of the device, and the anode-cathode voltage of the device will rise rapidly. Therefore, it can be determined that the moment when the rising rate of the anode-cathode voltage is higher than the predetermined threshold is the ending point of the storage stage.

[0095] Among them, the setting of the voltage threshold and the predetermined threshold can be obtained by performing a double-pulse test on the gate turn-off thyristor. Reasonably setting the voltage threshold and the predetermined threshold can further ensure the accuracy and effectiveness of the monitoring.

[0096] The device may further include: a processing unit, configured to perform digital signal processing on the voltage waveform to remove noise and improve the measurement accuracy before determining the storage time at different operating junction temperatures according to the voltage waveform. The first determination module includes: a fourth determination sub-module, configured to determine the storage time at different operating junction temperatures according to the voltage waveform after digital signal processing.

[0097] The digital signal processing methods include filtering, smoothing, peak detection, etc., to improve the accuracy and robustness of the storage time measurement through these methods. An adaptive filter can be used to adjust the filtering parameters according to the real-time change of the voltage waveform to remove the waveform noise and improve the signal quality.

[0098] According to some other embodiments of the present application, the acquisition module includes: a heating sub-module for heating the turn-off thyristor to multiple working junction temperatures by means of double-sided heating; an experiment sub-module for performing an active turn-off experiment on the turn-off thyristor at multiple working junction temperatures based on a double-pulse circuit, and measuring the change of the voltage between the anode and the cathode with time during the active turn-off experiment to obtain the voltage waveform; a measurement sub-module for measuring the working current of the turn-off thyristor in multiple active turn-off experiments through a Rogowski coil. In this embodiment, the double-sided heating method can more evenly control the junction temperature of the device, providing a good experimental basis for establishing a predetermined relationship among the storage time, the working current, and the working junction temperature; the double-pulse circuit is selected for the device experiment circuit to ensure the controllability and repeatability of the experimental conditions. Conducting the device experiment in the double-pulse test circuit can simulate the working conditions of the device in actual applications, which has important value for establishing a predetermined relationship applicable to the actual working conditions of the device; the measurement of the working current is carried out through a non-invasive Rogowski coil, which will not affect the normal operation of the device, can avoid interference with the device, and at the same time ensure the accuracy of the current data. Through the above method, rich device data can be obtained, providing data support for the accurate establishment of the subsequent predetermined relationship.

[0099] Specifically, the heating source of the double-sided heating method includes, but is not limited to, a ceramic heater or an infrared heating lamp, etc., to provide an accurate junction temperature control environment for facilitating data collection and the establishment of a predetermined relationship. The parameter adjustment of the double-pulse circuit includes, but is not limited to: adjusting the pulse width and frequency to adapt to the operating state of the device under different working currents; controlling the pulse voltage to ensure that the device does not enter an overload state and can accurately measure the storage time.

[0100] In addition, the method for obtaining the actual storage time and the actual working current is the same as the method for obtaining the storage time and the working current. That is, to obtain the actual storage time of the turn-off thyristor, the voltage waveform between the anode and the cathode of the turn-off thyristor can be obtained in real time, and then through a real-time data processing algorithm, the actual storage time can be obtained, ensuring that the measurement of the actual storage time can be carried out online and the response time meets the actual application requirements. The actual working current of the turn-off thyristor can be measured through a Rogowski coil.

[0101] Exemplarily, the second determination module includes one of the following: a fitting sub-module for performing data fitting on the data in the data set to obtain a function representing the predetermined relationship; an establishment sub-module for establishing a machine learning model and training the machine learning model based on the data set to obtain a target model representing the predetermined relationship. By fitting the data in the data set to obtain a function representing the predetermined relationship, the relationship between the operating junction temperature, operating current, and storage time of the turn-off thyristor can be accurately described in the form of a mathematical expression, which is beneficial to the monitoring of the actual operating junction temperature of the device; the machine learning model has a powerful non-linear mapping ability and can capture complex potential relationships in the data, thereby quantifying the complex relationship between the operating junction temperature, operating current, and storage time of the turn-off thyristor, which is beneficial to the monitoring of the actual operating junction temperature of the device.

[0102] Among them, the data fitting method includes but is not limited to polynomial fitting, exponential fitting, etc. The machine learning model includes but is not limited to support vector machine models, neural network models, deep network models, etc.

[0103] Of course, in addition to machine learning, other algorithms such as particle swarm optimization algorithms and genetic algorithms can also be used in this application to optimize the parameter selection in the data fitting process, so as to construct a more accurate mathematical model representing the relationship among the operating junction temperature, operating current, and storage time.

[0104] In some other embodiments of the present application, the device further includes at least one of the following: a third determination unit for, after determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship, determining the operating state of the turn-off thyristor according to the actual operating junction temperature. When the actual operating junction temperature is within the preset junction temperature range, it is determined that the operating state is normal; when the actual operating junction temperature is not within the preset junction temperature range, it is determined that the operating state is abnormal; a fourth determination unit for, after determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship, determining the actual thermal resistance of the turn-off thyristor according to the actual operating junction temperature, and determining the aging degree of the turn-off thyristor according to the actual thermal resistance. Determining the operating health state of the turn-off thyristor and / or determining the aging degree of the turn-off thyristor through the actual operating junction temperature of the device is beneficial to realizing fault prevention and proactive maintenance of the device where the device is located or the system, and optimizing the operating stability of the device or the system.

[0105] Specifically, dividing the actual junction temperature by the actual power of the device can obtain the actual thermal resistance of the device, and further, the aging degree of the device can be obtained according to the actual thermal resistance.

[0106] When the actual junction temperature exceeds a preset safety threshold, active intervention of the device's thermal management system is triggered, such as increasing the cooling efficiency of the radiator or adjusting the operating current of the device, to reduce the actual junction temperature of the device.

[0107] In other embodiments, the modular multilevel converter includes a plurality of MMC sub-modules, the MMC sub-module includes the turn-off thyristor, and the device further includes: a fifth determination unit, configured to determine the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship, and then determine the switching priority of the turn-off thyristor according to the actual operating junction temperatures of the plurality of turn-off thyristors, the greater the actual operating junction temperature, the smaller the corresponding switching priority; a control unit, configured to control the switching states of the plurality of thyristors according to the switching priorities of the plurality of thyristors to adjust the charging and discharging processes of the plurality of MMC sub-modules. In this embodiment, according to the actual junction temperatures of the turn-off thyristors in the plurality of MMC sub-modules, the switching priorities of the plurality of turn-off thyristors are controlled, so as to control the charging and discharging sequence of the plurality of MMC sub-modules, which can ensure the balance of the capacitor voltages of each MMC sub-module, realize the energy balance of the converter, and ensure a longer service life of the converter.

[0108] Specifically, the converter is composed of a plurality of MMC sub-modules with the same structure connected in series or in parallel. In addition to the turn-off thyristor, the MMC sub-module further includes components such as a capacitor and a diode. By controlling the conduction and turn-off of the turn-off thyristor, the input and removal of the MMC sub-module can be realized, thereby changing the output voltage of the converter. Common MMC sub-module topologies include half-bridge sub-modules, full-bridge sub-modules, etc. By controlling the number of input and removed sub-modules, output voltages of different levels can be synthesized. For example, in an MMC composed of half-bridge sub-modules, each sub-module can output two levels of 0 or the capacitor voltage. Through the combination of multiple sub-modules, output voltages of multiple levels can be obtained, making the output voltage waveform closer to a sine wave.

[0109] After obtaining the actual junction temperature, information interaction can be carried out with the control system of the converter to adjust the commutation strategy, so as to optimize the temperature distribution of the device and improve the operation efficiency and reliability of the converter.

[0110] In the actual application process, the dynamic characteristics of the device will change under different gate voltages. Therefore, a gate voltage compensation algorithm can be added to correct the predetermined relationship under different gate voltages of the device to ensure the accuracy of junction temperature measurement. For example, by introducing a voltage sensor, the actual gate voltage value of the turn-off thyristor is monitored in real time, and the coefficient in the predetermined relationship is adjusted according to this voltage value to achieve this.

[0111] The determining device for the operating junction temperature of the turn-off thyristor includes a processor and a memory. The first determining unit, the obtaining unit, the second determining unit, etc. are all stored in the memory as program units, and the processor executes the program units stored in the memory to implement corresponding functions. All the modules are located in the same processor; alternatively, the respective modules are located in different processors in any combined form.

[0112] The processor contains a kernel, and the kernel retrieves the corresponding program units from the memory. One or more kernels can be set, and by adjusting the kernel parameters, at least solve the problem that the junction temperature measurement of the turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0113] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, etc. forms, such as read-only memory (ROM) or flash memory (flash RAM), and the memory includes at least one storage chip.

[0114] An embodiment of the present invention provides a computer-readable storage medium, and the computer-readable storage medium includes a stored program, wherein when the program runs, it controls the device where the computer-readable storage medium is located to execute the method for determining the operating junction temperature of the turn-off thyristor.

[0115] An embodiment of the present invention provides a processor, and the processor is used to run a program, wherein when the program runs, it executes the method for determining the operating junction temperature of the turn-off thyristor.

[0116] An embodiment of the present invention provides a device, and the device includes a processor, a memory, and a program stored on the memory and executable on the processor. When the processor executes the program, it implements at least the following steps:

[0117] Step S201, determine a predetermined relationship characterizing the relationship among the storage time, operating current, and operating junction temperature of the turn-off thyristor. The storage time is the duration during which the turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the turn-off thyristor during the turn-off process, and the operating current is the current flowing through the turn-off thyristor before the turn-off thyristor actively turns off;

[0118] Step S202, obtain the actual storage time and actual operating current of the turn-off thyristor. The actual storage time is the actual storage time, and the actual operating current is the actual operating current;

[0119] Step S203: Determine the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0120] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0121] This application also provides a computer program product, which, when executed on a data processing device, is adapted to execute a program initialized with at least the following method steps:

[0122] Step S201: Determine a predetermined relationship characterizing the relationship among the storage time, the operating current, and the operating junction temperature of the turn-off thyristor. The storage time is the duration during which the turn-off thyristor is delayed in turning off due to the internal carrier storage effect of the turn-off thyristor during the turn-off process, and the operating current is the current flowing through the turn-off thyristor before the turn-off thyristor actively turns off;

[0123] Step S202: Obtain the actual storage time and the actual operating current of the turn-off thyristor. The actual storage time is the actual storage time, and the actual operating current is the actual operating current;

[0124] Step S203: Determine the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current, and the predetermined relationship.

[0125] Obviously, those skilled in the art should understand that the various modules or steps of the present invention can be implemented by a general-purpose computing device. They can be concentrated on a single computing device or distributed on a network composed of multiple computing devices. They can be implemented by program codes executable by the computing device. Thus, they can be stored in a storage device and executed by the computing device. And in some cases, the steps shown or described can be executed in a different order than here, or they can be separately fabricated into individual integrated circuit modules, or multiple modules or steps among them can be fabricated into a single integrated circuit module to implement. In this way, the present invention is not limited to any specific combination of hardware and software.

[0126] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0127] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, as well as the combination of flows and / or blocks in the flowchart and / or block diagram. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce means for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0128] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory produce a manufacture including instruction means that implement the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0129] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in the Figure 1 one or more flows and / or blocks Figure 1 one or more blocks.

[0130] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0131] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory such as read-only memory (ROM) or flash memory (flash RAM). The memory is an example of computer-readable media.

[0132] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0133] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0134] From the above description, it can be seen that the embodiments described in this application achieve the following technical effects:

[0135] 1), The method for determining the operating junction temperature of the turn-off thyristor in this application first determines the predetermined relationship between the storage time, the operating current before turn-off, and the operating junction temperature of the turn-off thyristor during the turn-off process; then obtains the actual storage time and the actual operating current of the turn-off thyristor; finally, determines the actual operating junction temperature of the turn-off thyristor based on the predetermined relationship, the actual storage time, and the actual operating current. This application uses the duration of the storage stage (i.e., the storage time) during the active turn-off process of the turn-off thyristor device as the temperature-sensitive electrical parameter, establishes the quantitative relationship among the storage time, the operating current, and the operating junction temperature of the turn-off thyristor, and determines the actual operating junction temperature of the device according to this quantitative relationship and the actual storage time and the actual operating current of the device. Since the storage time is sensitive to the change in the junction temperature, the sensitivity of the on-line monitoring of the device junction temperature is ensured. At the same time, since the storage time is not affected by the DC bus voltage, the interference of the DC bus voltage fluctuation on the device junction temperature is avoided, and the accuracy of the on-line monitoring of the device junction temperature is ensured, solving the problem that the junction temperature measurement of the turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0136] 2), The device for determining the operating junction temperature of the turn-off thyristor in this application determines the predetermined relationship between the storage time, the operating current before turn-off, and the operating junction temperature of the turn-off thyristor during the turn-off process through the first determination unit; obtains the actual storage time and the actual operating current of the turn-off thyristor through the acquisition unit; determines the actual operating junction temperature of the turn-off thyristor according to the predetermined relationship, the actual storage time, and the actual operating current through the second determination unit. This application uses the duration of the storage stage (i.e., the storage time) during the active turn-off process of the turn-off thyristor device as the temperature-sensitive electrical parameter, establishes the quantitative relationship among the storage time, the operating current, and the operating junction temperature of the turn-off thyristor, and determines the actual operating junction temperature of the device according to this quantitative relationship and the actual storage time and the actual operating current of the device. Since the storage time is sensitive to the change in the junction temperature, the sensitivity of the on-line monitoring of the device junction temperature is ensured. At the same time, since the storage time is not affected by the DC bus voltage, the interference of the DC bus voltage fluctuation on the device junction temperature is avoided, and the accuracy of the on-line monitoring of the device junction temperature is ensured, solving the problem that the junction temperature measurement of the turn-off thyristor device in the prior art is inaccurate, threatening the safe and stable operation of the system and equipment.

[0137] The above are only the preferred embodiments of this application and are not used to limit this application. For those skilled in the art, this application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

1. A method for determining the working junction temperature of a turn-off thyristor, characterized in that: include: Determining a predetermined relationship characterizing the relationship between the storage time, the operating current, and the operating junction temperature of the turn-off thyristor, wherein the storage time is the duration of the turn-off delay of the turn-off thyristor due to the internal carrier storage effect of the turn-off thyristor during the turn-off process, and the operating current is the current flowing through the turn-off thyristor before the turn-off thyristor is actively turned off; Acquire an actual storage time and an actual operating current of the turn-off thyristor, wherein the actual storage time is the actual storage time, and the actual operating current is the actual operating current; determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current and the predetermined relationship, The starting time of the storage time is the time when the voltage of the anode and cathode determined according to the voltage waveform is less than the voltage threshold, and the ending time of the storage time is the time when the voltage change rate of the anode and cathode determined according to the voltage waveform is greater than a predetermined threshold. The starting time of the storage time is the time when the commutation of the turn-off thyristor is completed, and the ending time of the storage time is the time when the space charge region of the device just begins to unfold and the anode voltage is rapidly established.

2. The method according to claim 1, characterized in that Determine a predetermined relationship characterizing the relationship between the storage time, operating current, and operating junction temperature of a turn-off thyristor, including: Acquire the operating current of the turn-off thyristor at different operating junction temperatures and the voltage waveforms of the anode and cathode of the turn-off thyristor; Determine the storage time at different operating junction temperatures according to the voltage waveform, and obtain a data set including a plurality of the operating junction temperatures, a corresponding plurality of the operating currents, and a corresponding plurality of the storage times; The predetermined relationship is determined according to the data set.

3. The method according to claim 2, characterized in that Determining the storage time at different operating junction temperatures according to the voltage waveform includes: According to the start time and the end time at different working junction temperatures, the storage time at different working junction temperatures is determined to be the difference between the end time and the start time.

4. The method according to claim 2, characterized in that: Obtaining the operating current of the turn-off thyristor at different operating junction temperatures and the voltage waveforms of the anode and cathode of the turn-off thyristor, including: heating the turn-off thyristor to a plurality of the operating junction temperatures by double-sided heating; Based on the double pulse circuit, an active shutdown experiment of the turn-off thyristor is performed at a plurality of the working junction temperatures, and the change of the voltage of the anode and cathode in the active shutdown experiment over time is measured to obtain the voltage waveform; The operating current of the turn-off thyristor in a plurality of active turn-off experiments is measured by a Rogowski coil.

5. The method according to claim 2, characterized in that: Determining the predetermined relationship according to the data set includes one of the following: Performing data fitting on the data in the data set to obtain a function that characterizes the predetermined relationship; A machine learning model is established, and the machine learning model is trained based on the data set to obtain a target model that represents the predetermined relationship.

6. The method according to any one of claims 1 to 5, characterized in that After determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current and the predetermined relationship, the method further includes at least one of the following: Determining an operating state of the turn-off thyristor according to the actual operating junction temperature, determining that the operating state is normal when the actual operating junction temperature is within a preset junction temperature range, and determining that the operating state is abnormal when the actual operating junction temperature is not within the preset junction temperature range; The actual thermal resistance of the SCR is determined according to the actual working junction temperature, and the aging degree of the SCR is determined according to the actual thermal resistance.

7. The method according to any one of claims 1 to 5, characterized in that The modular multilevel converter includes a plurality of MMC submodules, wherein the MMC submodule includes the turn-off thyristor. After determining the actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current and the predetermined relationship, the method further includes: Determining the switch priority of the turn-off thyristors according to the actual working junction temperatures of the plurality of turn-off thyristors, wherein the larger the actual working junction temperature is, the smaller the corresponding switch priority is; According to the switching priorities of the multiple thyristors, the switching states of the multiple thyristors are controlled to adjust the charging and discharging process of the multiple MMC sub-modules.

8. A device for determining the working junction temperature of a turn-off thyristor, characterized in that: include: A first determining unit is used to determine a predetermined relationship characterizing the relationship between the storage time, the operating current and the operating junction temperature of the turn-off thyristor, wherein the storage time is the time duration of the turn-off delay of the turn-off thyristor due to the internal carrier storage effect of the turn-off thyristor during the turn-off process, and the operating current is the current flowing through the turn-off thyristor before the turn-off thyristor is actively turned off; An acquisition unit, used for acquiring an actual storage time and an actual operating current of the turn-off thyristor, wherein the actual storage time is the actual storage time, and the actual operating current is the actual operating current; a second determining unit, configured to determine an actual operating junction temperature of the turn-off thyristor according to the actual storage time, the actual operating current and the predetermined relationship, The starting time of the storage time is the time when the voltage of the anode and cathode determined according to the voltage waveform is less than the voltage threshold, and the ending time of the storage time is the time when the voltage change rate of the anode and cathode determined according to the voltage waveform is greater than a predetermined threshold. The starting time of the storage time is the time when the commutation of the turn-off thyristor is completed, and the ending time of the storage time is the time when the space charge region of the device just begins to unfold and the anode voltage is rapidly established.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein when the program is executed, the device where the computer-readable storage medium is located is controlled to execute the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the one or more programs include methods for executing any one of claims 1 to 7.

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