A method, system, and storage medium for estimating the highest MOSFET temperature.

Abstract

This invention relates to the field of electronic circuit technology, specifically to a method, system, and storage medium for estimating the maximum MOSFET temperature. The problem addressed by this invention is how to accurately and quickly estimate the MOSFET junction temperature. To solve this problem, this invention provides a method for estimating the maximum MOSFET temperature, comprising: real-time acquisition of NTC temperature data to obtain first temperature data; if the first temperature data is greater than a first temperature threshold, obtaining MOSFET case temperature data based on the first temperature data and recording the case temperature data as second temperature data; real-time acquisition of MOSFET operating condition data and calculation of MOSFET loss data based on the operating condition data; obtaining the maximum junction temperature of the MOSFET based on the loss data and the second temperature data; and issuing an alarm message if the maximum junction temperature is greater than the second temperature threshold.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a method, system, and storage medium for estimating the maximum MOSFET temperature. Background Technology

[0002] In power electronic devices (such as switching power supplies, motor drivers, inverters, etc.), MOSFETs (metal-oxide-semiconductor field-effect transistors) are the core power switching devices, and their operating temperature directly affects the reliability and lifespan of the system. Excessively high junction temperatures can lead to MOSFET performance degradation or even permanent damage; therefore, real-time and accurate monitoring of MOSFET temperature is crucial. Currently, the industry commonly uses NTCs (negative temperature data thermistors) for temperature monitoring, indirectly reflecting the MOSFET's temperature state by measuring changes in the NTC's resistance.

[0003] However, this monitoring method has significant drawbacks in practical applications. Since NTCs are typically mounted on printed circuit boards (PCBs), while MOSFETs are often located in the center of heat sinks or areas of concentrated heat sources, the physical distance and differences in heat conduction paths between the two cause the temperature measured by the NTC to lag significantly behind the actual junction temperature of the MOSFET. For example, when the MOSFET junction temperature reaches 120°C, the NTC may only report a temperature signal of around 90°C, resulting in delayed triggering of over-temperature protection and potentially leading to serious consequences such as MOSFET overheating and burnout, or system shutdown. Furthermore, factors such as NTC mounting location deviations, contact thermal resistance, and ambient temperature gradients further exacerbate temperature measurement errors, making it difficult for NTC-based direct temperature monitoring methods to meet the accuracy and real-time requirements of high-reliability power systems.

[0004] Therefore, how to accurately and quickly estimate the junction temperature of MOSFETs has become a key technical issue for improving the thermal management performance and operational safety of power electronic devices. Summary of the Invention

[0005] The problem this invention solves is how to achieve accurate and rapid estimation of MOSFET junction temperature.

[0006] To address the aforementioned issues, this invention provides a method for estimating the maximum MOSFET temperature. The method includes: real-time acquisition of NTC temperature data to obtain first temperature data; if the first temperature data is greater than a first temperature threshold, obtaining MOSFET case temperature data based on the first temperature data and recording the case temperature data as second temperature data; real-time acquisition of MOSFET operating condition data and calculation of MOSFET loss data based on the operating condition data; obtaining the maximum junction temperature of the MOSFET based on the loss data and the second temperature data; if the maximum junction temperature is greater than the second temperature threshold, issuing an alarm message.

[0007] Compared with existing technologies, the technical effects achieved by this solution are as follows: By collecting NTC temperature data and MOSFET operating condition data in real time, and based on loss calculation and case temperature correlation analysis, the system error introduced by physical position deviation is effectively compensated, making the estimated temperature closer to the actual thermal state of the MOSFET chip. By collecting operating condition data (current, voltage, frequency, etc.) in real time to calculate losses, the dynamic changes of the "heat source" are incorporated into the temperature estimation in real time. This enables the system to respond to sudden load changes and predict the temperature rise caused by a sudden increase in power consumption in advance, significantly improving the predictability and timeliness of over-temperature protection. By calculating the maximum junction temperature in real time through algorithms and setting reasonable temperature thresholds, an alarm can be issued before the actual junction temperature of the MOSFET approaches the safety limit, triggering protection measures such as derating, current limiting, or shutdown.

[0008] In one embodiment of the present invention, the MOSFET case temperature data is obtained based on the first temperature data, and the case temperature data is recorded as the second temperature data. Specifically, this includes: calculating the correlation coefficient between the second temperature data and the first temperature data based on the environmental data and operating condition data of the MOSFET; and obtaining the second temperature data based on the correlation coefficient, the environmental data, the second temperature data and the correlation coefficient.

[0009] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: by introducing correlation analysis between environmental data and operating condition data, the difference in heat conduction path between NTC and MOSFET is effectively corrected, and the real-time performance and accuracy of case temperature estimation are significantly improved.

[0010] In one embodiment of the present invention, the correlation coefficient between the second temperature data and the first temperature data is calculated based on the environmental data and operating condition data of the MOSFET operation. Specifically, this includes: collecting the fluctuation of the first temperature data under various operating condition data in the same environmental data, and recording it as the first fluctuation data; collecting the fluctuation of the second temperature data under various operating condition data in the same environmental data, and recording it as the second fluctuation data; and obtaining the correlation coefficient between the second temperature data and the first temperature data in the current environmental data based on the first fluctuation data and the second fluctuation data.

[0011] Compared with existing technologies, the technical effects achieved by this solution are as follows: By analyzing the fluctuation characteristics of the first and second temperature data under the same environment, the correlation coefficient is calculated, effectively isolating environmental interference and enabling it to accurately capture the real-time changes in the heat conduction path between the NTC and MOSFET, thereby improving the accuracy of the correlation coefficient and its adaptability to operating conditions.

[0012] In one embodiment of the present invention, the operating condition data of the MOSFET is collected in real time, and the loss data of the MOSFET is calculated based on the operating condition data. Specifically, this includes: obtaining the current data, voltage data and resistance data of the MOSFET based on the operating condition data in the same environmental data; calculating the switching loss of the MOSFET based on the current data and voltage data; calculating the conduction loss of the MOSFET based on the current data and resistance data; and obtaining the loss data based on the switching loss and conduction loss.

[0013] Compared with existing technologies, the technical effects achieved by adopting this technical solution are as follows: using the same environmental data as the calculation premise, it isolates the interference of environmental fluctuations on current, voltage, and resistance parameters, ensuring that the loss calculation only reflects the changing patterns of operating condition data (current, voltage, and resistance), and making the loss data highly matched with the actual operating conditions.

[0014] In one embodiment of the present invention, the maximum junction temperature of the MOSFET is obtained based on loss data and second temperature data, specifically including: obtaining the thermal resistance parameter of the MOSFET; obtaining the temperature difference data between the maximum junction temperature and the second temperature data based on the product of the loss data and the thermal resistance parameter; and adding the temperature difference data to the second temperature data to obtain the maximum junction temperature of the MOSFET.

[0015] Compared with existing technologies, the technical effects achieved by this solution are as follows: by introducing a dynamic correlation between thermal resistance parameters and loss data, the physical mechanism-level accurate calculation of MOSFET junction temperature is realized, which can accurately reflect the changes in the thermal resistance characteristics of the device under different heat dissipation conditions.

[0016] In one embodiment of the present invention, a system for estimating the maximum MOSFET temperature is also provided. The method for estimating the maximum MOSFET temperature described in the above embodiment is applied to the system for estimating the maximum MOSFET temperature. The system includes: a data acquisition module for real-time acquisition of NTC temperature data and MOSFET operating condition data; a data calculation module for calculating MOSFET case temperature data, calculating MOSFET loss data based on operating condition data, and obtaining the maximum junction temperature of the MOSFET based on loss data and case temperature data; and an alarm module for issuing an alarm message when the maximum junction temperature exceeds a temperature threshold. This estimation system has all the technical features of the above estimation method, which will not be described in detail here.

[0017] In one embodiment of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the above-described method for estimating the maximum MOSFET temperature. Attached Figure Description

[0018] Figure 1This is a flowchart of a method for estimating the maximum MOSFET temperature according to the present invention; Figure 2 A schematic diagram illustrating the linear relationship between NTC temperature data and MOSFET case temperature data in the offline calibration experiment of this invention; Figure 3 A schematic diagram of a system for estimating the highest MOSFET temperature according to the present invention; Explanation of reference numerals in the attached figures: 100 - Estimation system; 110 - Data acquisition module; 120 - Data calculation module; 130 - Alarm module. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] [First Embodiment] See Figure 1 In one specific embodiment, the present invention provides a method for estimating the maximum MOSFET temperature, the estimation method comprising: S100: Real-time acquisition of NTC temperature data to obtain first temperature data. If the first temperature data is greater than the first temperature threshold, the MOSFET case temperature data is obtained based on the first temperature data, and the case temperature data is recorded as the second temperature data. S200: Real-time acquisition of MOSFET operating condition data, and calculation of MOSFET loss data based on the operating condition data; S300: Based on the loss data and the second temperature data, the highest junction temperature of the MOSFET is obtained. If the highest junction temperature is greater than the second temperature threshold, an alarm message is issued.

[0021] In step S100, the NTC temperature data can be collected in real time by the NTC thermistor attached near the MOSFET or on the heat dissipation path. Its resistance value exhibits a negative temperature coefficient characteristic as the temperature changes. The resistance value is converted into first temperature data through a preset resistance-temperature conversion model. Since there is a physical distance and heat conduction path difference between the NTC and MOSFET chips, directly using the first temperature data will cause a lag in junction temperature estimation. Therefore, it is necessary to obtain the second temperature data by using the correlation coefficient between the MOSFET case temperature data and the NTC temperature data obtained from the offline calibration experiment.

[0022] See Figure 2The relationship between NTC temperature and MOSFET case temperature data was tested through offline calibration experiments. It was found that under constant current, when the NTC temperature rises to 50℃, the NTC temperature and MOSFET case temperature data show a linear relationship. Since the application scenario is high temperature protection, the temperature before 50℃ can be ignored. When the NTC temperature sampling reaches 50℃, the second temperature data is obtained according to the correlation coefficient between the MOSFET case temperature data and the NTC temperature data. Therefore, the first temperature threshold can be set to 50℃.

[0023] It should be noted that when the first temperature data is less than or equal to the first temperature threshold, the MOSFET case temperature data will not be calculated.

[0024] In step S200, the operating condition data refers to key parameters such as current, voltage, frequency, and resistance of the MOSFET during actual operation. These data can be acquired in real time by a power analyzer or a dedicated sensor. For example, in switching power supply applications, the switching frequency of the MOSFET may dynamically adjust within the range of 50kHz to 200kHz as the load changes, and its conduction current may suddenly increase from 0.1A under no-load conditions to 10A under full load conditions. After obtaining these transient parameters through a high-speed sampling circuit, digital filtering is required to eliminate switching noise interference. Then, the switching loss is calculated based on the product of the effective value of the current and the instantaneous value of the voltage. At the same time, the conduction loss is calculated based on the product of the square of the effective value of the current and the conduction resistance. Finally, the two are superimposed to obtain the total loss data.

[0025] In addition, the actual loss data includes MOSFET losses and terminal losses, etc. Since the terminal losses are constant values ​​under different currents, only the MOSFET loss data is considered.

[0026] In step S300, by acquiring the thermal resistance parameters of the MOSFET (such as the junction-to-case thermal resistance RθJC), and combining them with the loss data, the temperature difference between the highest junction temperature and the second temperature data (ΔT = loss data × RθJC) can be calculated. Then, the temperature difference data is added to the second temperature data to obtain the highest junction temperature (highest junction temperature = second temperature data + ΔT). If the highest junction temperature exceeds the preset temperature threshold (such as 125℃), the alarm module triggers an audible and visual alarm or sends a control signal to the protection circuit to achieve over-temperature protection.

[0027] It should be noted that if the highest junction temperature is less than or equal to the second temperature threshold, no alarm message will be issued, and the calculation of the highest junction temperature will continue.

[0028] By collecting NTC temperature data and MOSFET operating condition data in real time, and based on loss calculation and case temperature correlation analysis, the system error introduced by physical position deviation is effectively compensated, making the estimated temperature closer to the actual thermal state of the MOSFET chip. By collecting operating condition data (current, voltage, frequency, etc.) in real time to calculate losses, the dynamic changes of the "heat source" are incorporated into the temperature estimation in real time. This enables the system to respond to sudden load changes and predict the temperature rise caused by a sudden increase in power consumption in advance, which significantly improves the predictability and timeliness of over-temperature protection. By calculating the maximum junction temperature in real time through the algorithm and setting a reasonable temperature threshold, an alarm can be issued before the actual junction temperature of the MOSFET approaches the safety limit, triggering protection measures such as derating, current limiting, or shutdown.

[0029] [Second Embodiment] In one specific embodiment, the MOSFET case temperature data is obtained based on the first temperature data, and the case temperature data is recorded as the second temperature data, specifically including: S110. Calculate the correlation coefficient between the second temperature data and the first temperature data based on the environmental data and operating condition data of the MOSFET. S120. Obtain the second temperature data based on the correlation coefficient, environmental data, second temperature data, and correlation coefficient.

[0030] In step S110, typically, before a new machine enters production, a series of tests and calibrations are performed to better understand its operating characteristics. For estimating the maximum temperature of a MOSFET, offline calibration experiments are a key step in obtaining the correlation coefficient. In the calibration experiment, the MOSFET is placed in a controllable environmental chamber to simulate different environmental conditions. At the same time, different current and voltage conditions are applied through a programmable power supply. High-precision temperature measuring instruments are used to simultaneously collect the first temperature data of the NTC and the actual case temperature data of the MOSFET chip surface (i.e., the second temperature data). Through regression analysis of a large amount of experimental data, a mathematical model is established regarding the relationship between environmental data (temperature, humidity), operating condition data (current, voltage, resistance) and the correlation coefficient. For example, under the operating conditions of an ambient temperature of 25℃, humidity of 50%RH, current of 5A, and voltage of 24V, if the first temperature data collected by the NTC is 60℃, and the actual case temperature of the MOSFET is 70℃, then the correlation coefficient is 70 / 60≈1.17. Through multiple sets of tests under similar operating conditions, the weight distribution of the correlation coefficient with respect to each variable can be obtained, thereby optimizing the model accuracy.

[0031] It should be noted that, through offline calibration experiments, it was found that under the same environmental conditions, the fitting curves of the NTC temperature and the MOSFET's highest junction temperature function are different under different currents. However, there is a fixed difference in the temperature rise difference under a fixed current. Therefore, after performing a single temperature calibration, a suffix value can be added to the fitting curve of temperature difference and current change.

[0032] For example, assuming that under the same environmental conditions, with current I1, when the NTC temperature is 70℃, the corresponding maximum junction temperature of the MOSFET is 100℃, and with current I2, when the NTC temperature is 70℃, the corresponding maximum junction temperature of the MOSFET is 115℃, then at the same NTC temperature point (70℃), there is a fixed difference in MOSFET temperatures between the two curves: 115℃ - 100℃ = 15℃. Therefore, under this environmental condition, the difference between the two NTC temperature and MOSFET maximum junction temperature function fitting curves with the same difference between I2 and I1 is 15℃.

[0033] In step S120, based on the correlation coefficient obtained in step S110, and combined with the real-time collected environmental data and the first temperature data, the second temperature data is calculated. The specific formula is as follows: Tc = k × Tntc + B; Where Tc is the second temperature data under the current environmental data, k is the correlation coefficient, Tntc is the first temperature data under the current environmental data, and B is the error value, which can be obtained experimentally.

[0034] By introducing correlation analysis between environmental data and operating condition data, the difference in heat conduction paths between NTC and MOSFET was effectively corrected, significantly improving the real-time performance and accuracy of case temperature estimation.

[0035] [Third Embodiment] In one specific embodiment, the correlation coefficient between the second temperature data and the first temperature data is calculated based on the environmental data and operating condition data of the MOSFET, specifically including: S111. In the same environmental data, collect the fluctuation of the first temperature data under each working condition data, and record it as the first fluctuation data. S112. In the same environmental data, collect the fluctuation of the second temperature data under various operating conditions and record it as the second fluctuation data. S113. Based on the first fluctuation data and the second fluctuation data, obtain the correlation coefficient between the second temperature data and the first temperature data in the current environmental data.

[0036] In steps S111 and S112, environmental data typically includes parameters such as ambient temperature, humidity, and air pressure. These parameters indirectly affect the heat transfer process between the MOSFET and NTC by influencing factors such as air thermal conductivity and thermal convection coefficient. For example, when the ambient temperature rises from 25°C to 50°C, the air density decreases, leading to a reduction in natural convection, which may cause the MOSFET heat dissipation efficiency to decrease by 10%-15%. At this time, it is necessary to simultaneously collect temperature fluctuation data of the NTC location and the MOSFET casing through a temperature sensor array. For example, an infrared thermal imager can be used to simultaneously collect MOSFET surface temperature and NTC temperature data.

[0037] Offline calibration experiments revealed that, under the same environmental conditions, the fitting curves of the NTC temperature and the MOSFET's highest junction temperature function differed under different currents. However, the temperature rise difference under a fixed current difference remained constant. Therefore, after single-temperature calibration, a suffix value could be added to the fitting curve of temperature difference versus current change.

[0038] For example, assuming that under the same environmental conditions, with current I1, when the NTC temperature is 70℃, the corresponding maximum junction temperature of the MOSFET is 100℃, and with current I2, when the NTC temperature is 70℃, the corresponding maximum junction temperature of the MOSFET is 115℃, then at the same NTC temperature point (70℃), there is a fixed difference in MOSFET temperatures between the two curves: 115℃ - 100℃ = 15℃. Therefore, under this environmental condition, the difference between the two NTC temperature and MOSFET maximum junction temperature function fitting curves with the same difference between I2 and I1 is 15℃.

[0039] In step S113, the formula for calculating the correlation coefficient between the second temperature data and the first temperature data in the current environmental data is as follows: k = Tc-t / Tntc-t; Where k is the correlation coefficient, Tc is any value in the second fluctuation data that is greater than the first temperature threshold, t is the first temperature threshold, and Tntc is the value in the first fluctuation data corresponding to Tc.

[0040] By analyzing the fluctuation characteristics of the first and second temperature data under the same environment, the correlation coefficient is calculated, effectively isolating environmental interference and accurately capturing the real-time change pattern of the heat conduction path between NTC and MOSFET, thus improving the accuracy of the correlation coefficient and the adaptability to operating conditions.

[0041] [Fourth Embodiment] In one specific embodiment, the operating condition data of the MOSFET is acquired in real time, and the loss data of the MOSFET is calculated based on the operating condition data, specifically including: S210. In the same environmental data, obtain the MOSFET's current data, voltage data, and resistance data based on the operating condition data; S220. Calculate the switching losses of the MOSFET based on the current and voltage data; S230. Calculate the MOSFET's conduction loss based on the current and resistance data; S240. Obtain loss data based on switching loss and conduction loss.

[0042] In step S210, the MOSFET loss data is the source of NTC temperature, MOSFET case temperature, and maximum junction temperature. Its accuracy directly affects the reliability of temperature estimation. The acquisition of operating condition data needs to cover the dynamic parameters throughout the entire operating cycle of the MOSFET. For example, in electric vehicle motor controller applications, the MOSFET current waveform may contain high-frequency switching spikes and low-frequency modulation envelopes. Millisecond-level sampling can be achieved using a Hall sensor with a bandwidth of not less than 1MHz. At the same time, synchronous rectification technology is used to eliminate the phase error introduced by the voltage probe. Finally, key parameters such as the effective value of current, instantaneous value of voltage, and on-resistance are extracted through digital filtering algorithms.

[0043] In step S220, the switching loss calculation needs to combine the MOSFET's switching frequency and gate drive parameters. For example, in a totem pole drive circuit, the turn-on delay time and turn-off delay time are calibrated using a double-pulse test method. Combined with current zero-crossing detection technology, the overlap loss in each switching cycle can be accurately calculated. The formula for calculating the switching loss is as follows: P switch = U × I × Miller coefficient × 8K × 2; Where P is the switching loss, U is the instantaneous voltage value, I is the effective current value, the Miller coefficient is determined by the gate charge characteristics of the MOSFET, 8K is a switching frequency related parameter (the coefficient needs to be adjusted according to the actual frequency), and 2 represents the superposition of the turn-on and turn-off losses within the switching cycle.

[0044] For example, at a switching frequency of 100kHz, if U=24V, I=5A, and Miller coefficient is 0.3, the single-cycle switching loss is approximately 0.72W. After obtaining the transient parameters of each cycle through a high-speed sampling circuit, the loss values ​​of 1000 consecutive cycles need to be processed by moving average to eliminate switching noise interference.

[0045] In step S230, the conduction loss calculation needs to consider the characteristic of the MOSFET's on-resistance changing with junction temperature. For example, a certain type of MOSFET has an on-resistance of 5mΩ at 25℃. When the junction temperature rises to 125℃, the on-resistance will increase to 8mΩ due to the decrease in carrier mobility of silicon material. The formula for calculating conduction loss is as follows: Pconduction = I² × Rds(on) × Kt; Where I is the effective value of the current, Rds(on) is the on-resistance at the current junction temperature, and Kt is the temperature correction factor (which can be obtained by fitting the Rds(on)-Tj curve in the device datasheet). For example, under a full load current of 10A, if the estimated real-time junction temperature is 100℃, the corresponding Rds(on) is 6.5mΩ, and the conduction loss is 0.65W. The Rds(on) parameter needs to be corrected by real-time junction temperature feedback to avoid loss calculation errors caused by temperature drift.

[0046] In step S240, the total loss data is the algebraic sum of switching loss and conduction loss. For example, under the above-mentioned operating conditions of 100kHz switching frequency and 10A full load, if the switching loss is 0.72W and the conduction loss is 0.65W, then the total loss is 1.37W.

[0047] By analyzing the fluctuation characteristics of the first and second temperature data under the same environment, the correlation coefficient is calculated, effectively isolating environmental interference and enabling it to accurately capture the real-time changes in the heat conduction path between the NTC and MOSFET, thus improving the accuracy of the correlation coefficient and its adaptability to operating conditions.

[0048] [Fifth Embodiment] In one specific embodiment, the highest junction temperature of the MOSFET is obtained based on loss data and second temperature data, specifically including: S310. Obtain the thermal resistance parameter of the MOSFET, and obtain the temperature difference between the highest junction temperature and the second temperature data based on the product of the loss data and the thermal resistance parameter. S320. Add the temperature difference data to the second temperature data to obtain the highest junction temperature of the MOSFET.

[0049] In step S310, the thermal resistance parameter refers to the resistance to heat transfer from the heat-generating area to the heat-dissipating area or the surrounding environment of the MOSFET. It reflects the heat dissipation capacity of the MOSFET under different operating conditions. Common thermal resistance parameters include junction-to-case thermal resistance, the values ​​of which can be obtained from the device datasheet or measured by professional thermal testing equipment. For example, the thermal resistance parameter of a certain type of MOSFET is 2℃ / W, which means that for every 1W of heat generated, the junction temperature will rise by 2℃ compared to the case temperature. Based on the loss data calculated earlier, such as a loss of 1.37W, the temperature difference between the highest junction temperature and the second temperature data ΔT = loss data × thermal resistance parameter = 1.37W × 2℃ / W = 2.74℃.

[0050] In step S320, the temperature difference data calculated in step S310 is added to the second temperature data to obtain the maximum junction temperature of the MOSFET. For example, if the second temperature data is 60℃ and the temperature difference data is 2.74℃, then the maximum junction temperature = second temperature data + ΔT = 60℃ + 2.74℃ = 62.74℃. In this way, the maximum junction temperature of the MOSFET under different operating conditions can be estimated more accurately, providing a basis for subsequent over-temperature protection and other operations.

[0051] The formula for calculating the maximum junction temperature is as follows: Tj = Tc + P_loss × R(thj); Where Tj is the highest junction temperature, Tc is the second temperature data, P_loss is the loss data, and R(thj) is the thermal resistance parameter.

[0052] Thermal resistance parameters need to be calibrated regularly to adapt to different heat dissipation conditions. For example, the thermal resistance of the same type of MOSFET may differ by 30%-50% under natural cooling and forced air cooling scenarios. By combining real-time loss data with dynamic thermal resistance parameters, the system can accurately predict the temperature evolution trend of power devices under extreme operating conditions, providing key data support for the reliability design of power electronic devices.

[0053] It should be noted that after MOSFETs are put into production, their key characteristics, such as thermal resistance and on-resistance, may drift due to factors such as machine wear and environmental changes. For example, after long-term operation, the interface thermal resistance between the MOSFET chip and the packaging material may increase by 20%-30% due to thermal stress cycling, while the decrease in carrier mobility of the silicon wafer will increase the on-resistance by 15%-20%. To address this drift, a dynamic calibration mechanism needs to be established. The dynamic calibration mechanism is as follows: S321. Obtain the frequency and cause of alarm anomalies, and correct the second temperature data and loss data according to the cause and frequency of alarm anomalies to obtain corrected second temperature data and corrected loss data. S322. The highest junction temperature is obtained based on the corrected second temperature data and the corrected loss data.

[0054] In step S321, alarm anomalies can be categorized into missed alarms and false alarms. Missed alarms may occur because the collected temperature data fails to accurately reflect the actual temperature state of the MOSFET. For example, an aging NTC sensor may cause a lower measured value, or obstructed heat conduction paths may delay case temperature transfer. False alarms may occur due to environmental interference or an excessively low second alarm threshold. For instance, strong electromagnetic interference may cause distortion of the sensor output signal, leading to an increased frequency of alarm anomalies. The frequency can be quantified by the ratio of the number of alarms triggered within a statistical period to the total running time. For example, if there are 3 false alarms per hour, the frequency is 0.05Hz. Combined with environmental parameter records in the alarm log (such as temperature fluctuation range and electromagnetic interference intensity), the root cause of the anomaly can be located. For missed alarm scenarios, an aging compensation coefficient needs to be superimposed on the second temperature data. This coefficient is obtained by fitting through offline accelerated aging experiments. For example, if the measurement deviation of an NTC sensor increases by 0.5℃ for every 1000 hours of operation, the compensation formula is Tntc_correction = T ntc_measured × (1 + 0.0005 × t), where t is the runtime; For false alarm scenarios, the second alarm threshold needs to be dynamically adjusted according to the type of environmental interference. For example, when the electromagnetic interference intensity exceeds 50 dBuV, the threshold should be increased by 10% to avoid false triggering. When correcting loss data, the on-resistance parameter needs to be updated synchronously, and the Rds(on) value should be corrected through real-time junction temperature feedback. For example, when the estimated junction temperature increases from 25℃ to 100℃, the on-resistance should be adjusted from 5mΩ to 6.5mΩ to ensure the accuracy of the on-resistance calculation.

[0055] In step S322, the corrected second temperature data and the corrected loss data are substituted into the maximum junction temperature calculation formula to obtain the estimated maximum junction temperature after dynamic calibration. For example, if the second temperature data before correction is 60℃, the loss data is 1.37W, and the thermal resistance parameter is 2℃ / W, and the second temperature data after correction is adjusted to 62℃ (to compensate for NTC aging deviation) and the loss data is adjusted to 1.5W (to compensate for on-resistance drift), then the maximum junction temperature = 62℃ + 1.5W × 2℃ / W = 65℃, which is 2.26℃ higher than the estimated value before correction and is closer to the actual junction temperature.

[0056] By introducing a dynamic correlation between thermal resistance parameters and loss data, a precise physical mechanism-level calculation of MOSFET junction temperature is achieved, which can accurately reflect the changes in the thermal resistance characteristics of the device under different heat dissipation conditions.

[0057] [Sixth Embodiment] See Figure 3In one specific embodiment, the present invention also provides a system for estimating the maximum MOSFET temperature. The method for estimating the maximum MOSFET temperature described in the above embodiment is applied to the system for estimating the maximum MOSFET temperature. The estimation system 100 includes: a data acquisition module 110, which is used to acquire NTC temperature data and MOSFET operating condition data in real time; a data calculation module 120, which is used to calculate the MOSFET case temperature data, calculate the MOSFET loss data based on the operating condition data, and obtain the maximum junction temperature of the MOSFET based on the loss data and the case temperature data; and an alarm module 130, which is used to issue an alarm message when the maximum junction temperature is greater than a temperature threshold. The estimation system 100 has all the technical features of the above estimation method, which will not be described in detail here.

[0058] In one embodiment of the present invention, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the above-described method for estimating the maximum MOSFET temperature.

[0059] The computer-readable storage medium can be located in a server, personal computer, mobile terminal or other electronic device. The computer program stored therein is run by a processor and can estimate the maximum temperature of the MOSFET in real time and accurately. When the estimated maximum junction temperature exceeds the preset temperature threshold, the system will quickly issue an alarm message to remind relevant personnel to take timely measures, such as derating, current limiting or shutdown, to prevent the MOSFET from being damaged due to overheating and to ensure the stable operation of the entire electronic system.

[0060] It should be noted that the above description of the implementation method and its beneficial effects also applies to the estimation system and computer-readable medium of the present invention. To avoid redundancy, it will not be elaborated further here.

[0061] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for estimating the highest MOSFET temperature, characterized in that, The estimation method includes: Real-time acquisition of NTC temperature data to obtain first temperature data; if the first temperature data is greater than a first temperature threshold, then the MOSFET case temperature data is obtained based on the first temperature data, and the case temperature data is recorded as the second temperature data. Real-time acquisition of the MOSFET's operating condition data, and calculation of the MOSFET's loss data based on the operating condition data; The maximum junction temperature of the MOSFET is obtained based on the loss data and the second temperature data. If the maximum junction temperature is greater than the second temperature threshold, an alarm message is issued.

2. The estimation method according to claim 1, characterized in that, The step of obtaining the MOSFET's case temperature data based on the first temperature data and recording the case temperature data as the second temperature data specifically includes: Based on the environmental data of the MOSFET operation and the operating condition data, calculate the correlation coefficient between the second temperature data and the first temperature data; The second temperature data is obtained based on the correlation coefficient, the environmental data, the second temperature data, and the correlation coefficient.

3. The estimation method according to claim 2, characterized in that, The step of calculating the correlation coefficient between the second temperature data and the first temperature data based on the environmental data of the MOSFET operation and the operating condition data specifically includes: In the same environmental data, the fluctuation of the first temperature data under each of the operating conditions is collected and recorded as the first fluctuation data; In the same environmental data, the fluctuation of the second temperature data under each of the operating conditions is collected and recorded as the second fluctuation data; The correlation coefficient between the second temperature data and the first temperature data in the current environmental data is obtained based on the first fluctuation data and the second fluctuation data.

4. The estimation method according to claim 3, characterized in that, The real-time acquisition of the MOSFET's operating condition data and the calculation of the MOSFET's loss data based on the operating condition data specifically include: In the same environmental data, the current data, voltage data and resistance data of the MOSFET are obtained based on the operating condition data; The switching losses of the MOSFET are calculated based on the current data and the voltage data. The conduction loss of the MOSFET is calculated based on the current data and the resistance data; The loss data is obtained based on the switching loss and the conduction loss.

5. The estimation method according to claim 4, characterized in that, The step of obtaining the maximum junction temperature of the MOSFET based on the loss data and the second temperature data specifically includes: Obtain the thermal resistance parameter of the MOSFET, and obtain the temperature difference data between the highest junction temperature and the second temperature data based on the product of the loss data and the thermal resistance parameter; The temperature difference data is added to the second temperature data to obtain the highest junction temperature of the MOSFET.

6. A system for estimating the highest MOSFET temperature, characterized in that, The estimation method according to any one of claims 1 to 5 is applied to the estimation system, the estimation system comprising: A data acquisition module is used to acquire NTC temperature data and MOSFET operating condition data in real time. The data calculation module is used to calculate the case temperature data of the MOSFET, calculate the loss data of the MOSFET based on the operating condition data, and obtain the maximum junction temperature of the MOSFET based on the loss data and the case temperature data. An alarm module is used to issue an alarm message when the highest junction temperature exceeds a temperature threshold.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the estimation method as described in any one of claims 1 to 5.

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