Converter stage igbt junction temperature monitoring method, device, electronic equipment and medium

Abstract

The application relates to the technical field of power electronic converter state monitoring, in particular to a converter stage IGBT junction temperature monitoring method and device, electronic equipment and a medium, wherein the method comprises the following steps: obtaining the current state and the current DC bus leakage current of a converter, and obtaining the current junction temperature of the converter and matching the optimal switching frequency of the converter stage IGBT based on the mapping relationship between the DC bus leakage current and the junction temperature, so as to control the conduction state of the IGBT. Therefore, the problems that the device level monitoring circuit is difficult to integrate in the junction temperature monitoring process, the structure of the converter needs to be adjusted, the monitoring cost is high, and a large leakage current measurement error is caused are solved, the measurement circuit is installed on the DC bus, the leakage current is extracted from the DC bus in a delayed manner, and the junction temperature is monitored, so that the converter can be plug and play without adjusting the structure, the monitoring cost and the leakage current measurement error are reduced.

Description

Technical Field

[0001] This application relates to the field of power electronic converter condition monitoring technology, and in particular to a method, device, electronic equipment and medium for monitoring the junction temperature of converter-level IGBTs (Insulated Gate Bipolar Transistors). Background Technology

[0002] In recent years, the penetration rate of power electronic converters has gradually increased, with widespread applications in new energy power generation and electric vehicles. This means that increasingly important application scenarios and harsh operating environments pose challenges to the reliability of converters. According to reports, converters have the highest failure rate and maintenance costs among power electronic systems; therefore, improving converter reliability and reducing its failure rate is crucial. Excessive junction temperature and junction temperature fluctuations in semiconductor devices within the converter are the main factors leading to their failure. Therefore, online junction temperature monitoring is fundamental to improving converter reliability.

[0003] Among related technologies, junction temperature monitoring methods mainly include physical contact methods, optical measurement methods, thermal model methods, and thermistor electrical parameter methods. Physical contact methods require placing thermistors or thermocouples inside the device under test, which is highly invasive and has a slow response speed, making them unsuitable for online monitoring. Optical measurement methods typically use infrared thermal imagers to obtain the temperature field distribution; this method is not only costly but also requires the device under test to be encapsulated for light transmission. Thermal model methods require complex calculations of parameters in the thermal network, resulting in a low response speed. Thermistor electrical parameter methods have been widely studied in recent years and have gradually become the mainstream method for online junction temperature monitoring. Their principle is to indirectly reflect the junction temperature by measuring electrical parameters that have a certain mathematical relationship with the junction temperature.

[0004] Common thermistor parameters include on-state voltage drop, gate threshold voltage, on-state resistance, switching delay, and leakage current. Junction temperature monitoring methods based on these parameters have been proven to have certain application value through laboratory testing, but they are difficult to promote and popularize in actual industry. The fundamental reason is that current thermistor parameter methods are only for power electronic devices (device-level monitoring methods) rather than the converter as a whole, which brings a series of problems: (1) Device-level monitoring methods lead to excessively high monitoring costs. A typical three-phase two-level converter usually contains 6 switching devices, such as insulated gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs), and each device requires an independent monitoring circuit, thus greatly increasing the monitoring cost; (2) Device-level monitoring circuits are difficult to integrate, which is not conducive to reducing the size of the converter and increasing the power density; (3) Device-level monitoring methods require adjustments to the converter structure, which is very difficult for converters that have already been put into use. Therefore, there is still a lack of a converter-level junction temperature monitoring method to solve the above problems and truly promote the application of online junction temperature monitoring in industry. The essence of converter-level junction temperature monitoring methods is to extract junction temperature information of various devices from the external electrical parameters of the converter. Common external electrical parameters include phase (line) voltage, phase current, DC bus voltage, and DC bus current. However, developing converter-level junction temperature monitoring methods faces some difficulties: (1) External electrical parameters are often coupled with thermistor parameters of various devices, making it difficult to distinguish these parameters; (2) Extracting thermistor parameters from external parameters is more susceptible to electromagnetic interference, thereby reducing measurement accuracy; (3) Due to the influence of stray parameters, there may be differences between internal and external measurements of thermistor parameters.

[0005] Therefore, based on the above analysis, there is an urgent need for a converter-level junction temperature monitoring method to solve the problems existing in device-level junction temperature monitoring methods. Summary of the Invention

[0006] This application provides a converter-level IGBT junction temperature monitoring method, device, electronic device, and medium to solve problems such as difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and large leakage current measurement errors.

[0007] The first aspect of this application provides a method for monitoring the junction temperature of a converter-level IGBT, including the following steps:

[0008] Obtain the current state of the converter and the current DC bus leakage current;

[0009] Based on the mapping relationship between DC bus leakage current and junction temperature, the current junction temperature of the converter is obtained according to the current state and the current DC bus leakage current; and

[0010] The optimal switching frequency of the IGBT at the current junction temperature is matched to that of the converter stage IGBT, and the conduction state of the IGBT is controlled according to the optimal switching frequency.

[0011] According to one embodiment of the present invention, before obtaining the current junction temperature of the converter based on the current state and the current DC bus leakage current according to the mapping relationship between the DC bus leakage current and the junction temperature, the method further includes:

[0012] Based on the first increasing strategy, the junction temperature of the converter is heated from a first temperature to a second temperature;

[0013] Based on the second increase strategy, the DC bus voltage is increased from the first voltage to the second voltage;

[0014] According to the preset temperature interval, the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages is obtained;

[0015] By fitting the DC bus leakage current under the multiple junction temperatures and multiple DC bus voltages using an exponential function, the mapping relationship between the DC bus leakage current and the junction temperature is obtained.

[0016] According to one embodiment of the present invention, obtaining the current junction temperature of the converter based on the mapping relationship between DC bus leakage current and junction temperature, according to the current state and the current DC bus leakage current, includes:

[0017] The current delay state of the converter is determined based on the current state;

[0018] If the current delay state is the first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is the second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs.

[0019] Based on the mapping relationship between the DC bus leakage current and the junction temperature, the average junction temperature of the lower bridge arm IGBT is obtained according to the sum of the leakage currents of the lower bridge arm IGBT, and the average junction temperature of the upper bridge arm IGBT is obtained according to the sum of the leakage currents of the upper bridge arm IGBT.

[0020] The current junction temperature of the converter is obtained based on the average junction temperature of the lower IGBT and / or the average junction temperature of the upper IGBT.

[0021] According to one embodiment of the present invention, before obtaining the current state of the converter and the current DC bus leakage current, the method further includes:

[0022] Determine if the current monitoring duration is the preset monitoring duration;

[0023] If the current monitoring duration is the preset monitoring duration, then the current state of the converter and the current DC bus leakage current are obtained.

[0024] According to one embodiment of the present invention, after obtaining the current state of the converter and the current DC bus leakage current, the method further includes:

[0025] Reset the current monitoring duration to zero.

[0026] According to one embodiment of the present invention, the preset monitoring duration is 100 microseconds.

[0027] According to the converter-level IGBT junction temperature monitoring method of this application, the current state of the converter and the current DC bus leakage current are obtained. Based on the mapping relationship between the DC bus leakage current and the junction temperature, the current junction temperature of the converter is obtained and matched with the optimal switching frequency of the converter-level IGBT, thereby controlling the conduction state of the IGBT. This solves the problems of difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors. By installing the measurement circuit on the DC bus and extracting the leakage current from it for junction temperature monitoring, a plug-and-play converter design can be achieved without structural adjustments, reducing monitoring costs and leakage current measurement errors.

[0028] A second aspect of this application provides a converter-level IGBT junction temperature monitoring device, comprising:

[0029] The first acquisition module is used to acquire the current state of the converter and the current DC bus leakage current.

[0030] The second acquisition module is used to obtain the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current; and

[0031] The control module is used to match the optimal switching frequency of the converter-stage IGBT according to the current junction temperature, and to control the conduction state of the IGBT according to the optimal switching frequency.

[0032] According to an embodiment of the present invention, before obtaining the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current, the second acquisition module is further configured to:

[0033] Based on the first increasing strategy, the junction temperature of the converter is heated from a first temperature to a second temperature;

[0034] Based on the second increase strategy, the DC bus voltage is increased from the first voltage to the second voltage;

[0035] According to the preset temperature interval, the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages is obtained;

[0036] By fitting the DC bus leakage current under the multiple junction temperatures and multiple DC bus voltages using an exponential function, the mapping relationship between the DC bus leakage current and the junction temperature is obtained.

[0037] According to one embodiment of the present invention, the second acquisition module is specifically used for:

[0038] The current delay state of the converter is determined based on the current state;

[0039] If the current delay state is the first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is the second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs.

[0040] Based on the mapping relationship between the DC bus leakage current and the junction temperature, the average junction temperature of the lower bridge arm IGBT is obtained according to the sum of the leakage currents of the lower bridge arm IGBT, and the average junction temperature of the upper bridge arm IGBT is obtained according to the sum of the leakage currents of the upper bridge arm IGBT.

[0041] The current junction temperature of the converter is obtained based on the average junction temperature of the lower IGBT and / or the average junction temperature of the upper IGBT.

[0042] According to an embodiment of the present invention, before acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module is specifically used for:

[0043] Determine if the current monitoring duration is the preset monitoring duration;

[0044] If the current monitoring duration is the preset monitoring duration, then the current state of the converter and the current DC bus leakage current are obtained.

[0045] According to an embodiment of the present invention, after acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module is specifically used for:

[0046] Reset the current monitoring duration to zero.

[0047] According to one embodiment of the present invention, the preset monitoring duration is 100 microseconds.

[0048] According to the converter-level IGBT junction temperature monitoring device of this application embodiment, by acquiring the current state of the converter and the current DC bus leakage current, and based on the mapping relationship between the DC bus leakage current and the junction temperature, the current junction temperature of the converter is obtained, and the optimal switching frequency of the converter-level IGBT is matched, thereby controlling the conduction state of the IGBT. This solves the problems of difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors. By installing the measurement circuit on the DC bus and extracting the leakage current from it for junction temperature monitoring, plug-and-play functionality is achieved without structural adjustments, reducing monitoring costs and leakage current measurement errors.

[0049] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the converter-level IGBT junction temperature monitoring method as described in the above embodiments.

[0050] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the converter-level IGBT junction temperature monitoring method as described in the above embodiments.

[0051] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0052] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0053] Figure 1 This is a schematic diagram of an online leakage current measurement circuit in related technologies;

[0054] Figure 2 This is a schematic diagram illustrating the relationship between leakage current and crystallization in IGBTs in related technologies.

[0055] Figure 3 This is a schematic diagram of the steps of a converter stage junction temperature monitoring method according to an embodiment of this application;

[0056] Figure 4 This is a flowchart of a converter-level IGBT junction temperature monitoring method according to an embodiment of this application;

[0057] Figure 5 For an embodiment of the present application, I is provided leakDC A schematic diagram of the offline measurement results;

[0058] Figure 6 This is a schematic diagram of the converter state and corresponding bus current waveform according to an embodiment of this application;

[0059] Figure 7 This is a schematic diagram of bus current and leakage current measurement results using the state delay method according to an embodiment of this application;

[0060] Figure 8 This is a schematic diagram of the line voltage and bus current waveforms in an online experiment according to an embodiment of this application;

[0061] Figure 9 This is a schematic diagram of online monitoring results provided according to an embodiment of this application;

[0062] Figure 10 This is an example diagram of a converter-level IGBT junction temperature monitoring device according to an embodiment of this application;

[0063] Figure 11 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. Detailed Implementation

[0064] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0065] The following description, with reference to the accompanying drawings, outlines a converter-level IGBT junction temperature monitoring method, apparatus, electronic device, and dielectric according to embodiments of this application. Addressing the issues mentioned in the background art, such as the difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors, this application provides a converter-level IGBT junction temperature monitoring method. In this method, the current state of the converter and the current DC bus leakage current are obtained, and based on the mapping relationship between the DC bus leakage current and the junction temperature, the current junction temperature of the converter is calculated and matched with the optimal switching frequency of the converter-level IGBT, thereby controlling the IGBT's conduction state. This solves the problems of difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors. By installing the measurement circuit on the DC bus and extracting the leakage current from it for junction temperature monitoring, a plug-and-play converter design can be achieved without structural adjustments, reducing monitoring costs and leakage current measurement errors.

[0066] Before introducing the embodiments of this application, let's first introduce the IGBT junction temperature monitoring method based on leakage current in the related art.

[0067] Specifically, such as Figure 1 As shown, the circuit consists of two anti-parallel diodes and a measuring resistor. When the monitored IGBT is in the on-state, the large on-state current mainly flows through the diodes, so the voltage drop across the measuring resistor is clamped to around 0.7V. When the monitored IGBT is in the resistive state, the leakage current is insufficient to turn on the diodes, so the leakage current flows through the measuring resistor. In this case, the voltage drop across the measuring resistor reflects the magnitude of the leakage current. The leakage current of the IGBT is related to the junction temperature and the bus voltage. According to relevant semiconductor physics theories, the leakage current and junction temperature have an approximately exponential relationship, such as... Figure 2 As shown, the leakage current increases with rising junction temperature, and the rate of increase accelerates. Therefore, given a known bus voltage, the leakage current can be used to estimate the junction temperature of the IGBT chip.

[0068] The above technical solutions have some technical defects: (1) This method is a semiconductor device-level junction temperature method, and therefore has the common problems of device-level junction temperature monitoring methods, namely, high monitoring cost, unfavorable for converter integration, and the need to change the converter design structure; (2) This method has a large monitoring error. During converter operation, the duration of each resistive state of the IGBT under test is short, while the current commutation between the diode and the resistor in the measurement circuit takes time. Therefore, there may be a situation where the IGBT resistive state ends, but the commutation process of the measurement circuit has not yet ended, causing a large leakage current measurement error.

[0069] Therefore, in response to the aforementioned device-level junction temperature monitoring method, this application embodiment will address the problems existing in the device-level junction temperature monitoring method by employing a converter-level junction temperature monitoring method, such as... Figure 3 As shown, the following discussion will take the junction temperature monitoring of a three-phase two-level converter composed of six HGTG20N60B3DIGBTs as an example.

[0070] Specifically, Figure 4 This is a flowchart illustrating a converter-level IGBT junction temperature monitoring method provided in an embodiment of this application.

[0071] like Figure 4 As shown, the converter-level IGBT junction temperature monitoring method includes the following steps:

[0072] In step S401, the current state of the converter and the current DC bus leakage current are obtained.

[0073] Furthermore, in some embodiments, before obtaining the current state of the converter and the current DC bus leakage current, the method further includes: determining whether the current monitoring duration is a preset monitoring duration; if the current monitoring duration is a preset monitoring duration, then obtaining the current state of the converter and the current DC bus leakage current.

[0074] Furthermore, in some embodiments, after obtaining the current state of the converter and the current DC bus leakage current, the method further includes: clearing the current monitoring duration to zero.

[0075] The preset monitoring duration can be a threshold set by the user or a threshold obtained through multiple computer simulations; no specific limitation is made here.

[0076] Specifically, after the monitored converter starts working, the monitoring period T in the DSP (Digital Signal Processor) is... m The timer starts counting. The monitoring period T is... m Indicates every T m During the duration, the DSP will capture the current state of the converter once, i.e., either state code 111 or 000, and measure I. leakDC Therefore, T m This determines the accuracy of junction temperature monitoring. Preferably, in practical applications, the T in the embodiments of this application... m The preset monitoring duration can be set to 100 microseconds.

[0077] Furthermore, when the timer reaches the monitoring period T m At this time, the DSP begins to capture the 000 or 111 state of the converter and sends a state delay signal, at which point the monitoring duration of the DSP counter is cleared to zero.

[0078] In step S402, based on the mapping relationship between DC bus leakage current and junction temperature, the current junction temperature of the converter is obtained according to the current state and the current DC bus leakage current.

[0079] Furthermore, in some embodiments, before obtaining the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature according to the current state and the current DC bus leakage current, the method further includes: heating the junction temperature of the converter from a first temperature to a second temperature based on a first increasing strategy; increasing the DC bus voltage from a first voltage to a second voltage based on a second increasing strategy; acquiring multiple junction temperatures and DC bus leakage currents under multiple DC bus voltages according to a preset temperature interval; and obtaining the mapping relationship between the DC bus leakage current and the junction temperature by fitting the multiple junction temperatures and DC bus leakage currents under multiple DC bus voltages using an exponential function.

[0080] Further, in some embodiments, based on the mapping relationship between DC bus leakage current and junction temperature, the current junction temperature of the converter is obtained according to the current state and the current DC bus leakage current, including: determining the current delay state of the converter based on the current state; if the current delay state is a first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is a second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs; based on the mapping relationship between DC bus leakage current and junction temperature, the average junction temperature of the lower bridge arm IGBTs is obtained according to the sum of the leakage currents of the lower bridge arm IGBTs, and the average junction temperature of the upper bridge arm IGBTs is obtained according to the sum of the leakage currents of the upper bridge arm IGBTs; the current junction temperature of the converter is obtained according to the average junction temperature of the lower bridge arm IGBTs and / or the average junction temperature of the upper bridge arm IGBTs.

[0081] Specifically, in this embodiment, the DC leakage current I is first determined through offline experimental testing. leakDC and junction temperature T j The relationship between them is stored in the DSP. During offline experimental testing, the converter's junction temperature was heated from 25℃ (first temperature) to 150℃ (second temperature), and measurements were taken every 25℃; the bus voltage V bus The voltage was gradually increased from 50V (the first voltage) to 450V (the second voltage), and the leakage current in the DC bus was measured at various junction temperatures and bus voltages. The results are as follows: Figure 5 As shown.

[0082] Furthermore, embodiments of this application Figure 5 I leakDC Offline measurement results can be represented by an exponential function:

[0083]

[0084] Where A and B are two coefficients independent of junction temperature, the specific fitting results are shown in Table 1, R 2 The regression coefficients are used for fitting. The junction temperature can be calculated from the leakage current using equation (1).

[0085] Table 1

[0086]

[0087]

[0088] Furthermore, such as Figure 6 As shown, it illustrates the converter's state and the bus current I. busThe waveform is shown. Q1, Q3, and Q5 represent the drive voltages of the upper IGBTs, with 1 indicating a high level and 0 indicating a low level. In the 000 state, since there is no current loop between the positive and negative terminals of the DC bus, the bus current is the sum of the leakage currents of the three upper IGBTs. At the instant of entering the 000 state, if the timer reaches its monitoring cycle, the converter begins a 20-microsecond state delay.

[0089] Specifically, I in the embodiments of this application leakDC The leakage current is measured by the online leakage current measurement circuit in the delayed 000 or 111 state, and the DSP is based on the offline measured I. leakDC and T j Calculate the relationship between T j .like Figure 7 As shown, the output result V of the measurement circuit after the state delay is displayed. mea This refers to measuring the voltage drop across the resistor (100Ω) and the waveform of the bus current. Where V... mea The reduction requires a transition process, and the state delay rule can guarantee V. mea The transition phase is completed before leakage current measurement.

[0090] Furthermore, such as Figure 7 The measurement stage shown can be based on V mea Calculate I leakDC In other words, when the converter is in a 111 delay state, the resulting I... leakDC It is the sum of the leakage currents of the lower bridge arm IGBTs; when the converter is in the 000 delay state, the obtained I leakDC This is the sum of the leakage currents of the upper bridge arm IGBTs. Therefore, based on the mapping relationship between the DC bus leakage current and the junction temperature, the average junction temperature of the lower bridge arm IGBT is obtained from the sum of its leakage currents, and the average junction temperature of the upper bridge arm IGBT is obtained from the sum of its leakage currents. That is, in the 111 delay state, the average junction temperature of the lower bridge arm IGBT is obtained; in the 000 delay state, the average junction temperature of the upper bridge arm IGBT is obtained. Finally, the current junction temperature of the converter is calculated using equation (1) based on the average junction temperature of the lower bridge arm IGBT and / or the average junction temperature of the upper bridge arm IGBT.

[0091] In summary, based on the analysis using the methods described above, and by determining the DC leakage current I through offline experimental measurement... leakDC and junction temperature T j In the process of establishing the relationship, it is also necessary to verify it. The specific verification method is as follows:

[0092] Specifically, such as Figure 8As shown in (a) and (b), the line voltage waveform and DC bus current waveform after adding the state delay method during the test are displayed. It can be seen from the figure that during the state delay stage, the waveforms of line voltage and bus current are temporarily defaulted. During this stage, the measurement of bus leakage current has little impact on the overall output of the converter.

[0093] Furthermore, observe its monitoring results, such as Figure 9 As shown in (a) and (b), T mea The junction temperature is calculated based on the proposed converter-level IGBT junction temperature monitoring method, where T is the junction temperature. ref The reference junction temperature is used. It can be seen that under various temperature conditions, this method has a monitoring error of less than 3%.

[0094] In step S403, the optimal switching frequency of the IGBT in the converter stage is matched according to the current junction temperature, and the conduction state of the IGBT is controlled according to the optimal switching frequency.

[0095] Specifically, the control strategy of the converter-level IGBT in this application embodiment can be adjusted according to the calculated current junction temperature to extend the device's lifespan. That is, if the monitored junction temperature is too high, the switching frequency of the device can be appropriately reduced to lower the junction temperature by reducing losses, thereby ensuring that the IGBT's conduction state is controlled at the optimal switching frequency and extending the device's lifespan.

[0096] In summary, the main inventive points of the embodiments of this application are:

[0097] (1) Utilizing the leakage current I in the bus current leakDC As a junction temperature monitoring indicator, this parameter has an exponential relationship with the average junction temperature of the upper or lower arm of the converter. Therefore, it can be extracted from the bus current. leakDC Real-time monitoring of junction temperature.

[0098] (2)I leakDC The measurement method, namely the state delay method, captures the converter's 111 or 000 state at each monitoring cycle, and then delays for 20 microseconds. This measurement method can improve I... leakDC The measurement accuracy.

[0099] (3) Combining I leakDC A converter-level junction temperature monitoring strategy based on state delay method. In the 111 delay state, the temperature is monitored by measuring I... leakDC The average junction temperature of the IGBT on the upper arm of the converter can be obtained; in the 000 delay state, by measuring I... leakDC The average junction temperature of the IGBT in the lower bridge arm of the converter can be obtained.

[0100] Therefore, the advantages of the embodiments of this application compared with related technologies are as follows:

[0101] (1) Addressing the issue of excessively high monitoring costs in device-level junction temperature monitoring methods: This invention is a converter-level junction temperature monitoring method that extracts leakage current from the DC bus to monitor the junction temperature. Therefore, each converter only requires one measurement circuit, greatly reducing the monitoring cost, which can theoretically be reduced to 1 / 6 of the original method.

[0102] (2) Regarding the difficulties in integrating device-level junction temperature monitoring circuits and the need to adjust the converter structure: The measurement circuit of this method is installed on the DC bus rather than inside the converter, so it does not affect the size of the converter or have integration difficulties. On the other hand, it can be used plug-and-play for converters that are already in use without the need to adjust the internal structure of the converter.

[0103] (3) To address the problem of large online leakage current measurement error: The state delay method in this invention delays the leakage current measurement by 20 microseconds in each 111 or 000 state of the bus leakage current to be measured, which can effectively solve the leakage current measurement error caused by excessive transient time of the measurement circuit.

[0104] According to the converter-level IGBT junction temperature monitoring method of this application, the current state of the converter and the current DC bus leakage current are obtained. Based on the mapping relationship between the DC bus leakage current and the junction temperature, the current junction temperature of the converter is obtained and matched with the optimal switching frequency of the converter-level IGBT, thereby controlling the conduction state of the IGBT. This solves the problems of difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors. By installing the measurement circuit on the DC bus and extracting the leakage current from it for junction temperature monitoring, a plug-and-play converter design can be achieved without structural adjustments, reducing monitoring costs and leakage current measurement errors.

[0105] Next, with reference to the accompanying drawings, a converter-level IGBT junction temperature monitoring device according to an embodiment of this application is described.

[0106] Figure 10 This is a block diagram of a converter-level IGBT junction temperature monitoring device according to an embodiment of this application.

[0107] like Figure 10 As shown, the converter-level IGBT junction temperature monitoring device 10 includes: a first acquisition module 100, a second acquisition module 200, and a control module 300.

[0108] The first acquisition module 100 is used to acquire the current state of the converter and the current DC bus leakage current.

[0109] The second acquisition module 200 is used to obtain the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current; and

[0110] The control module 300 is used to match the optimal switching frequency of the converter-level IGBT according to the current junction temperature, and to control the conduction state of the IGBT according to the optimal switching frequency.

[0111] Furthermore, in some embodiments, before obtaining the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current, the second acquisition module 200 is further configured to:

[0112] Based on the first increase strategy, the junction temperature of the converter is heated from the first temperature to the second temperature;

[0113] Based on the second increase strategy, the DC bus voltage is increased from the first voltage to the second voltage;

[0114] According to the preset temperature interval, the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages is obtained;

[0115] By fitting the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages using an exponential function, the mapping relationship between DC bus leakage current and junction temperature is obtained.

[0116] Furthermore, in some embodiments, the second acquisition module 200 is specifically used for:

[0117] Determine the current delay state of the converter based on the current state;

[0118] If the current delay state is the first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is the second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs.

[0119] Based on the mapping relationship between DC bus leakage current and junction temperature, the average junction temperature of the lower bridge arm IGBT is obtained from the sum of the leakage currents of the lower bridge arm IGBT, and the average junction temperature of the upper bridge arm IGBT is obtained from the sum of the leakage currents of the upper bridge arm IGBT.

[0120] The current junction temperature of the converter is obtained based on the average junction temperature of the lower arm IGBT and / or the average junction temperature of the upper arm IGBT.

[0121] Furthermore, in some embodiments, before acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module 100 is specifically used for:

[0122] Determine if the current monitoring duration is the preset monitoring duration;

[0123] If the current monitoring duration is the preset monitoring duration, then obtain the current status of the converter and the current DC bus leakage current.

[0124] Furthermore, in some embodiments, after acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module 100 is specifically used for:

[0125] Reset the current monitoring duration to zero.

[0126] Furthermore, in some embodiments, the preset monitoring duration is 100 microseconds.

[0127] According to the converter-level IGBT junction temperature monitoring device of this application embodiment, by acquiring the current state of the converter and the current DC bus leakage current, and based on the mapping relationship between the DC bus leakage current and the junction temperature, the current junction temperature of the converter is obtained, and the optimal switching frequency of the converter-level IGBT is matched, thereby controlling the conduction state of the IGBT. This solves the problems of difficulty in integrating device-level monitoring circuits during junction temperature monitoring, the need to adjust the converter structure, high monitoring costs, and significant leakage current measurement errors. By installing the measurement circuit on the DC bus and extracting the leakage current from it for junction temperature monitoring, plug-and-play functionality of the converter can be achieved without structural adjustments, reducing monitoring costs and leakage current measurement errors.

[0128] Figure 11 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include:

[0129] The memory 1101, the processor 1102, and the computer program stored on the memory 1101 and executable on the processor 1102.

[0130] When the processor 1102 executes the program, it implements the converter-level IGBT junction temperature monitoring method provided in the above embodiments.

[0131] Furthermore, electronic devices also include:

[0132] Communication interface 1103 is used for communication between memory 1101 and processor 1102.

[0133] The memory 1101 is used to store computer programs that can run on the processor 1102.

[0134] The memory 1101 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0135] If the memory 1101, processor 1102, and communication interface 1103 are implemented independently, then the communication interface 1103, memory 1101, and processor 1102 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be divided into address buses, data buses, control buses, etc. For ease of representation, Figure 11 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0136] Optionally, in a specific implementation, if the memory 1101, processor 1102, and communication interface 1103 are integrated on a single chip, then the memory 1101, processor 1102, and communication interface 1103 can communicate with each other through an internal interface.

[0137] The processor 1102 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0138] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the converter-level IGBT junction temperature monitoring method described above.

[0139] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0140] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0141] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0142] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0143] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0144] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware, and the program can be stored in a computer-readable storage medium. When executed, the program includes one or a combination of the steps of the method embodiments.

[0145] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0146] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for monitoring the junction temperature of a converter-level IGBT, characterized in that, Includes the following steps: Obtain the current state of the converter and the current DC bus leakage current; Based on the mapping relationship between DC bus leakage current and junction temperature, the current junction temperature of the converter is obtained according to the current state and the current DC bus leakage current; as well as The optimal switching frequency of the IGBT in the current junction temperature converter stage is matched, and the conduction state of the IGBT is controlled according to the optimal switching frequency. The method of obtaining the current junction temperature of the converter based on the mapping relationship between DC bus leakage current and junction temperature, according to the current state and the current DC bus leakage current, includes: determining the current delay state of the converter based on the current state; If the current delay state is the first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is the second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs; based on the mapping relationship between the DC bus leakage current and the junction temperature, the average junction temperature of the lower bridge arm IGBTs is obtained according to the sum of the leakage currents of the lower bridge arm IGBTs, and the average junction temperature of the upper bridge arm IGBTs is obtained according to the sum of the leakage currents of the upper bridge arm IGBTs; the current junction temperature of the converter is obtained according to the average junction temperature of the lower bridge arm IGBTs and / or the average junction temperature of the upper bridge arm IGBTs.

2. The method according to claim 1, characterized in that, Before obtaining the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current, the method further includes: Based on the first increasing strategy, the junction temperature of the converter is heated from a first temperature to a second temperature; Based on the second increase strategy, the DC bus voltage is increased from the first voltage to the second voltage; According to the preset temperature interval, the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages is obtained; By fitting the DC bus leakage current under the multiple junction temperatures and multiple DC bus voltages using an exponential function, the mapping relationship between the DC bus leakage current and the junction temperature is obtained.

3. The method according to claim 1, characterized in that, Before obtaining the current state of the converter and the current DC bus leakage current, the method further includes: Determine if the current monitoring duration is the preset monitoring duration; If the current monitoring duration is the preset monitoring duration, then the current state of the converter and the current DC bus leakage current are obtained.

4. The method according to claim 3, characterized in that, After obtaining the current state of the converter and the current DC bus leakage current, the method further includes: Reset the current monitoring duration to zero.

5. The method according to claim 3, characterized in that, The preset monitoring duration is 100 microseconds.

6. A converter-level IGBT junction temperature monitoring device, characterized in that, include: The first acquisition module is used to acquire the current state of the converter and the current DC bus leakage current. The second acquisition module is used to obtain the current junction temperature of the converter based on the mapping relationship between DC bus leakage current and junction temperature, according to the current state and the current DC bus leakage current; as well as The control module is used to match the optimal switching frequency of the converter-stage IGBT according to the current junction temperature, and control the conduction state of the IGBT according to the optimal switching frequency. The second acquisition module is specifically used for: determining the current delay state of the converter based on the current state; if the current delay state is a first delay state, then the current DC bus leakage current is the sum of the leakage currents of the lower bridge arm IGBTs; if the current delay state is a second delay state, then the current DC bus leakage current is the sum of the leakage currents of the upper bridge arm IGBTs; based on the mapping relationship between the DC bus leakage current and the junction temperature, obtaining the average junction temperature of the lower bridge arm IGBTs based on the sum of the leakage currents of the lower bridge arm IGBTs, obtaining the average junction temperature of the upper bridge arm IGBTs based on the sum of the leakage currents of the upper bridge arm IGBTs; obtaining the current junction temperature of the converter based on the average junction temperature of the lower bridge arm IGBTs and / or the average junction temperature of the upper bridge arm IGBTs.

7. The apparatus according to claim 6, characterized in that, Before obtaining the current junction temperature of the converter based on the mapping relationship between the DC bus leakage current and the junction temperature, according to the current state and the current DC bus leakage current, the second acquisition module is further configured to: Based on the first increasing strategy, the junction temperature of the converter is heated from a first temperature to a second temperature; Based on the second increase strategy, the DC bus voltage is increased from the first voltage to the second voltage; According to the preset temperature interval, the DC bus leakage current under multiple junction temperatures and multiple DC bus voltages is obtained; By fitting the DC bus leakage current under the multiple junction temperatures and multiple DC bus voltages using an exponential function, the mapping relationship between the DC bus leakage current and the junction temperature is obtained.

8. The apparatus according to claim 6, characterized in that, Before acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module is specifically used for: Determine if the current monitoring duration is the preset monitoring duration; If the current monitoring duration is the preset monitoring duration, then the current state of the converter and the current DC bus leakage current are obtained.

9. The apparatus according to claim 8, characterized in that, After acquiring the current state of the converter and the current DC bus leakage current, the first acquisition module is specifically used for: Reset the current monitoring duration to zero.

10. The apparatus according to claim 8, characterized in that, The preset monitoring duration is 100 microseconds.

11. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the converter-level IGBT junction temperature monitoring method as described in any one of claims 1-5.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the converter-level IGBT junction temperature monitoring method as described in any one of claims 1-5.

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