Thermal resistance transient overload test method and system for power electronic component

Abstract

The invention provides a power electronic component thermal resistance transient overload test method and system, and the method comprises the following steps: building a test platform, carrying out the initialization calibration of a test environment, and enabling the test platform to be integrated with a power drive module; the high-frequency sampling and dynamic adjusting technology is adopted, temperature, voltage and current data are collected at the sampling rate not lower than 10 kHz, the sampling interval is adjusted according to the thermal time constant, the advanced sensor and calibration technology is combined, coupling changes of temperature and electrical parameters are accurately captured, and the testing precision is improved; meanwhile, by means of a hardware synchronous clock and a rapid data processing technology, full-time tracking of rapid fluctuation of thermal resistance in the transient overload process is achieved, key characteristic parameters such as a thermal resistance peak value and response time are accurately extracted, and a reliable basis is provided for performance evaluation of components; in addition, various transient power waveforms and combinations thereof are supported, abundant transient overload working conditions are preset, a complex overload scene is simulated, and the practicability and reliability of the test are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly relates to a method and system for testing the transient overload of the thermal resistance of power electronic components. Background Art

[0002] In a power electronic system, the thermal resistance characteristics of power electronic components are key factors affecting their reliability and lifespan. Under transient overload conditions, the temperature of the components changes rapidly, and accurate measurement of the thermal resistance is crucial for evaluating the performance and reliability of the components. In the prior art, thermal resistance measurement methods are usually based on steady-state conditions or simple transient operating conditions, and are evaluated by measuring the relationship between temperature and power consumption. However, there are still certain problems:

[0003] First, the measurement accuracy is insufficient. In the process of high-frequency transient overload, affected by the response speed of sensors, signal noise, and model parameter errors, it is difficult to accurately capture the dynamic coupling changes between temperature and electrical parameters;

[0004] Second, the ability of real-time dynamic monitoring is lacking. The data sampling rate and processing efficiency of existing systems are relatively low, and it is impossible to track the rapid fluctuations of thermal resistance during the transient overload process in real time, resulting in large extraction errors of key transient characteristic parameters (such as thermal resistance peak value, response time);

[0005] Third, the adaptability to complex overload scenarios is poor. Existing measurement methods are mostly aimed at a single type of transient waveform (such as fixed pulse width pulses), and it is difficult to simulate diverse overload operating conditions in actual operation (such as multi-waveform superposition, variable amplitude step, random intermittent overload, etc.), resulting in insufficient matching between the test results and the actual application scenarios;

[0006] Therefore, a method and system for testing the transient overload of the thermal resistance of power electronic components are proposed. Summary of the Invention

[0007] In view of this, embodiments of the present invention hope to provide a method and system for testing the transient overload of the thermal resistance of power electronic components to solve or alleviate the technical problems existing in the prior art, and at least provide a beneficial option.

[0008] To solve the above technical problems, a technical solution adopted in the present application is: a method for testing the transient overload of the thermal resistance of power electronic components, including the following steps:

[0009] Step 1, build a test platform and initialize and calibrate the test environment. The test platform integrates a power driving module;

[0010] Step 2, apply an initial constant power to the power electronic component under test through the power driving module. After the temperature of the power electronic component under test stabilizes, record the initial temperature, initial voltage, and initial current at this time, and calculate the initial thermal resistance;

[0011] Step 3: Generate a corresponding transient power waveform according to the preset transient overload condition, and apply the transient overload power to the power electronic component under test through the power drive module according to this transient power waveform;

[0012] Step 4: During the application of the transient overload power, collect the temperature, voltage, and current data of the power electronic component under test in real time at a high-frequency sampling rate not lower than 10 kHz, and record the sampling time at the same time;

[0013] Step 5: Preprocess the collected temperature, voltage, and current data, remove noise and outliers, and perform time synchronization calibration;

[0014] Step 6: Based on the transient thermal resistance model, combine the preprocessed temperature, voltage, and current data to calculate the transient thermal resistance of the power electronic component under test at different moments during the transient overload process;

[0015] Step 7: According to the evaluation index, analyze the change curve of the transient thermal resistance, evaluate the transient overload performance of the thermal resistance of the power electronic component under test, and generate an evaluation report.

[0016] Preferably as a further aspect of the present technical solution, in Step 4, the high-frequency sampling rate is dynamically adjusted according to the thermal time constant of the power electronic component under test, and the sampling interval satisfies the formula:

[0017]

[0018] where f max is the highest frequency component of the transient power waveform.

[0019] Preferably as a further aspect of the present technical solution, in Step 3, the transient power waveform includes a pulse type, a step type, a sine type, or a combination of any two or more waveforms, and the preset transient overload conditions include different overload amplitudes, overload durations, and overload interval times.

[0020] Preferably as a further aspect of the present technical solution, in Step 6, the transient thermal resistance model is a lumped parameter model or a distributed parameter model established based on the heat transfer principle, and the parameters of the transient thermal resistance model are calibrated through the physical structure parameters, material thermal conductivity, and boundary conditions of the power electronic component under test.

[0021] Preferably as a further aspect of the present technical solution, in Step 2, the formula for calculating the initial thermal resistance is:

[0022]

[0023] where T initial is the initial temperature, Tambient is the ambient temperature, P initial is the initial constant power.

[0024] Preferably further as the technical solution of the present application, in step one, the test platform includes a test fixture, a power driving module, a temperature sensor, a voltage sensor and a current sensor;

[0025] The test fixture is used to fix the power electronic component to be tested;

[0026] The temperature sensor is attached to the surface or key heat generating area of the power electronic component to be tested, and is connected to the power driving module, the voltage sensor and the current sensor;

[0027] The voltage sensor and the current sensor are respectively used to collect the voltage across and the current flowing through the power electronic component to be tested.

[0028] Preferably further as the technical solution of the present application, in step seven, the evaluation indexes include the peak value of the transient thermal resistance, the time to reach the peak value, the thermal resistance recovery time, and the stability of the thermal resistance change; the evaluation report includes test data, test curves and test conclusions.

[0029] To solve the above technical problems, another technical solution adopted by the present application is: a power electronic component transient thermal overload test system, the system includes: a test platform building module, a steady-state reference test module, a transient power generation module, a high-frequency synchronous acquisition module, a data preprocessing module, a transient thermal resistance calculation module and a performance evaluation report module;

[0030] The test platform building module is configured to build a test platform and perform initial calibration on the test environment, and the test platform integrates a power driving module;

[0031] The steady-state reference test module is configured to apply an initial constant power to the power electronic component to be tested through the power driving module, and after the temperature of the power electronic component to be tested tends to be stable, record the initial temperature, initial voltage and initial current at this time, and calculate the initial thermal resistance;

[0032] The transient power generation module is configured to generate a corresponding transient power waveform according to a preset transient overload condition, and apply a transient overload power to the power electronic component to be tested through the power driving module according to the transient power waveform;

[0033] The high-frequency synchronous acquisition module is configured to, during the application of the transient overload power, collect the temperature, voltage and current data of the power electronic component to be tested in real time at a high-frequency sampling rate not lower than 10 kHz, and record the sampling time at the same time;

[0034] The data preprocessing module is configured to preprocess the collected temperature, voltage, and current data, remove noise and outliers, and perform time synchronization calibration;

[0035] The transient thermal resistance calculation module is configured to calculate the transient thermal resistance of the measured power electronic component at different times during the transient overload process based on the transient thermal resistance model and in combination with the preprocessed temperature, voltage, and current data;

[0036] The performance evaluation report module is configured to analyze the change curve of the transient thermal resistance according to the evaluation index, evaluate the transient overload performance of the thermal resistance of the measured power electronic component, and generate an evaluation report.

[0037] Preferably further as the technical solution of the present invention, the test platform building module integrates a power driving module, and the power driving module includes a waveform generator and a power amplifier;

[0038] The waveform generator is configured to generate pulse-type, step-type, sine-type, or combined-type transient power waveforms;

[0039] The power amplifier is configured to amplify the waveform signal to the rated power range of the measured component and apply transient overload power.

[0040] Preferably further as the technical solution of the present invention, the data preprocessing module includes a preprocessing unit and a thermal resistance calculation unit;

[0041] The preprocessing unit is configured to perform noise suppression and outlier rejection using digital filtering algorithms and the 3σ criterion, and perform multi-sensor data time synchronization through hardware triggering or software interpolation;

[0042] The thermal resistance calculation unit is configured to call the lumped parameter model or the distributed parameter model, calibrate the model parameters in combination with the physical structure parameters of the measured component, the thermal conductivity of the material, and the boundary conditions, and calculate the transient thermal resistance value in real time.

[0043] Due to the adoption of the above technical solutions in the embodiments of the present invention, the following advantages are achieved:

[0044] 1. By applying high-frequency sampling and dynamic adjustment technologies, the present invention collects temperature, voltage, and current data in real time at a sampling rate not lower than 10 kHz, adjusts the sampling interval according to the thermal time constant, and combines advanced sensors and calibration technologies to accurately capture the coupled changes of temperature and electrical parameters during the transient process, effectively reducing measurement errors and improving test accuracy;

[0045] 2. Through the hardware synchronous clock and fast data processing technologies, the present invention realizes full-time tracking of the rapid fluctuations of the thermal resistance during the transient overload process, accurately extracts key characteristic parameters such as the thermal resistance peak value and response time, and provides a reliable basis for component performance evaluation;

[0046] 3. By supporting a variety of transient power waveforms and their combinations, the present invention presets a rich variety of transient overload conditions, covering different overload amplitudes, durations, and intervals, highly simulating complex overload scenarios in actual operation, making the test results more in line with actual applications, and enhancing the practicality and reliability of the tests.

[0047] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will be readily apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 It is a schematic flow chart of a method for testing the thermal resistance transient overload of a power electronic component according to the present invention;

[0050] Figure 2 It is a schematic diagram of the functional modules of a system for testing the thermal resistance transient overload of a power electronic component according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The following will describe the embodiments of the present disclosure in detail with reference to the drawings.

[0052] It should be clear that the following illustrates the embodiments of the present disclosure through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts belong to the scope of protection of the present disclosure.

[0053] Note that the following description relates to various aspects of embodiments within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is for illustrative purposes only. Based on this disclosure, those skilled in the art should understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement a device and / or practice a method. Additionally, this device and / or method can be implemented using other structures and / or functionality in addition to one or more of the aspects described herein.

[0054] It should also be noted that the diagrams provided in the following embodiments only schematically illustrate the basic concept of the present disclosure. The components shown in the diagrams only relate to those related to the present disclosure and are not drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0055] In addition, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the aspects described can be practiced without these specific details.

[0056] Figure 1 It is a schematic flowchart of a method for testing the thermal resistance transient overload of a power electronic component according to an embodiment of the present invention. Note that if there are substantially the same results, the method of the present application is not limited to Figure 1 the process sequence shown. As Figure 1 shown: A method for testing the thermal resistance transient overload of a power electronic component includes the following steps:

[0057] Step 1: Build a test platform and initialize and calibrate the test environment. The test platform integrates a power drive module;

[0058] Among them, the specific steps for building the test platform are as follows:

[0059] First, prepare the test equipment and materials, specifically including:

[0060] Prepare a suitable test fixture to ensure that it can firmly fix the power electronic component to be tested and has good thermal conductivity to ensure that the temperature sensor can accurately measure the temperature of the component;

[0061] Select a power drive module, which should have the ability to output an initial constant power and a transient overload power that meet the test requirements, and have good power regulation accuracy and stability;

[0062] Prepare high-precision temperature sensors, such as thermocouples or infrared temperature sensors, to ensure that their measurement accuracy can meet the test requirements and can quickly respond to temperature changes;

[0063] Select appropriate voltage sensors and current sensors to collect the voltage across and current flowing through the device under test. The sensors should have good linearity and anti-interference capabilities;

[0064] Prepare other auxiliary equipment, such as oscilloscopes, data acquisition cards, etc., to monitor and record relevant data during the test;

[0065] Then, install the test equipment, specifically including:

[0066] Install the test fixture on a stable workbench to ensure its position is fixed and there will be no shaking or displacement during the test;

[0067] Install the power electronic device under test on the test fixture, pay attention to the accurate installation position, and ensure good contact between the device and the fixture to ensure effective heat transfer;

[0068] Attach the temperature sensor to the surface of the device under test or the key heat-generating area, and use thermal conductive materials (such as thermal conductive silicone) to fill the gap between the sensor and the device to improve the heat transfer efficiency and ensure the accuracy of temperature measurement;

[0069] Connect the voltage sensor and current sensor to both ends of the device under test respectively, ensure the connection is firm, and pay attention to the correct connection of the positive and negative poles of the sensors to avoid measurement errors;

[0070] Connect the power drive module to the test fixture, voltage sensor, and current sensor, ensure the connection is correct, and pay attention to electrical safety to avoid accidents such as short circuits or electric shocks;

[0071] Connect auxiliary equipment such as oscilloscopes and data acquisition cards to the corresponding sensors and power drive modules to ensure the normal operation of the data acquisition and monitoring system;

[0072] Finally, connect the power supply and signal lines, specifically including:

[0073] Connect the power supply of the test system to a suitable power outlet, ensure the power supply voltage is stable, and pay attention to the good grounding of the power supply to avoid electrical interference;

[0074] Connect the signal lines of each sensor and power drive module to the data acquisition card or other data processing devices, ensure the signal line connection is correct, and pay attention to the shielding of the signal lines to avoid the influence of external interference on the measurement data.

[0075] The specific steps for initializing and calibrating the test environment are as follows:

[0076] First, according to the test requirements, use a thermo-hygrostat or other environmental control equipment to set the initial environmental temperature and humidity; generally speaking, the environmental temperature should be set within the normal operating temperature range of the device under test, and the humidity should be maintained at a relatively stable level to avoid the influence of environmental factors on the test results;

[0077] Then, turn on the thermo-hygrostat to make it start working, and adjust the temperature and humidity inside the box to gradually reach the preset initial conditions; during the adjustment process, closely monitor the display panel of the thermo-hygrostat to ensure that the changes in temperature and humidity are within a reasonable range, and pay attention to the air circulation inside the box to ensure the uniformity of temperature and humidity; wait until the temperature and humidity inside the thermo-hygrostat are stable within the preset initial condition range and remain for a certain period (usually 30 minutes to 1 hour) to ensure the stability of the test environment; during the stabilization process, regularly check the operating status of the thermo-hygrostat to ensure its normal operation, and record the changes in environmental temperature and humidity for reference when analyzing the test results later;

[0078] Next, during the stabilization of the test environment, conduct a comprehensive inspection of the test equipment to ensure its normal operation; the inspection contents include:

[0079] Check whether the connections of the temperature sensor, voltage sensor, and current sensor are firm, and whether there is any looseness or poor contact;

[0080] Check whether the output of the power drive module is normal, and whether it can output the initial constant power and transient overload power according to the preset requirements;

[0081] Check whether the working status of auxiliary equipment such as oscilloscopes and data acquisition cards is normal, and whether they can accurately collect and record test data;

[0082] Check the fixing condition of the test fixture to ensure that the device under test will not be displaced or loosened during the test;

[0083] Subsequently, use a standard thermometer and hygrometer to measure the actual temperature and humidity inside the thermo-hygrostat, compare them with the preset initial conditions, and make corresponding adjustments if there are any deviations until the actual temperature and humidity match the preset conditions; when performing environmental calibration, pay attention to the selection of the measurement position, and a representative position inside the thermo-hygrostat should be selected for measurement to ensure the accuracy of the measurement results;

[0084] Finally, after the test environment calibration is completed, record the initial environmental temperature, humidity, and other relevant environmental parameters (such as air pressure, etc.), which will be used as important reference bases for subsequent test result analysis.

[0085] Step 2: Apply an initial constant power to the power electronic component under test through the power drive module. After the temperature of the power electronic component under test stabilizes, record the initial temperature, initial voltage, and initial current at this time, and calculate the initial thermal resistance;

[0086] Specifically, first, according to the rated power of the component under test and the test requirements, set the initial constant power value P initial (such as 50% of the rated power or the industry standard test power); confirm that the output mode of the power drive module is the "constant power mode", and calibrate the output accuracy (such as verifying that the power output error ≤ ±1% through a standard load resistor); at the same time, connect the output terminal of the power drive module in series to the main circuit of the component under test, ensure that the positive and negative poles are correctly connected, connect a current sensor (such as a Hall current sensor) in series in the loop, and connect a voltage sensor (such as an isolated voltage probe) in parallel; and turn on the power of the power drive module to start the preheating process (such as preheating for 10 minutes to avoid the influence of device temperature drift on power stability);

[0087] Then, send an instruction through the control module to make the power drive module output the set initial constant power P initial , and at the same time trigger the data acquisition system to start recording the timestamp; and use an oscilloscope to monitor the voltage and current waveforms in real time to ensure that there is no spike interference or power oscillation. If an abnormality occurs, adjust the filtering parameters of the power drive module or recalibrate;

[0088] At the same time, use a high-precision thermocouple sensor (accuracy ±0.1 °C) or an infrared thermal imager to collect the surface or junction temperature of the component under test at a sampling rate of 1 Hz; and define the determination condition for "temperature tending to be stable": the fluctuation range of 10 consecutive temperature sampling values ≤ ±0.5 °C; and the temperature change rate between two adjacent samplings ≤ 0.1 °C / min, and the duration ≥ 10 minutes; when the above conditions are met, the data acquisition system automatically triggers the stable state mark;

[0089] Next, after the stable state mark is triggered, synchronously record the following data:

[0090] Initial temperature T initial : Take the average value of the last 5 temperature samplings in the stable stage (unit: °C);

[0091] Initial voltage V initial : The effective value collected by the voltage sensor (unit: V);

[0092] Initial current I initial : The effective value collected by the current sensor (unit: A);

[0093] Ambient temperature T ambient: The temperature (unit: °C) monitored in real time inside the thermostatic and humidistatic chamber;

[0094] And according to the thermal resistance definition formula:

[0095]

[0096] Calculate the initial steady-state thermal resistance (unit: °C / W); where, P initial = V initial × I initial (If the power drive module directly outputs the power value, it can be directly called); Meanwhile, the data recording system automatically stores the calculation result and generates a steady-state test data file (including timestamp, original waveform, calculation process);

[0097] Finally, perform exception handling and repeated verification. If the temperature continues to rise beyond the safety threshold (such as exceeding 80% of the maximum junction temperature of the component) after applying power, the power drive module automatically cuts off the power and triggers an alarm, and records the exception log; If the three stable determinations all fail (such as excessive temperature fluctuations), prompt to check the sensor adhesion, the thermal conductivity of the fixture, or the environmental calibration status;

[0098] Meanwhile, to improve the data reliability, the initial power can be applied repeatedly 2 - 3 times, with an interval of 30 minutes each time (waiting for the component to cool down completely to the ambient temperature), and the average value of the multiple initial thermal resistances is taken as the reference value.

[0099] Step 3: Generate the corresponding transient power waveform according to the preset transient overload condition, and apply the transient overload power to the power electronic component under test through the power drive module according to this transient power waveform;

[0100] Specifically, first, through the control software of the test system (such as LabVIEW or customized GUI), input or select the transient overload condition parameters, specifically including:

[0101] Waveform type: Pulse type (single pulse / multi-pulse), step type (single step / periodic step), sine type (variable frequency and variable amplitude), or combined type (such as pulse superposed step);

[0102] Overload amplitude: The multiple relative to the initial constant power (such as 1.5 times, 2 times the rated power);

[0103] Duration: The duration of a single overload pulse / step / sine wave (such as 5ms, 100ms);

[0104] Interval time: The interval between two adjacent overload events (for periodic overload tests, such as interval 1s);

[0105] Number of cycles: The total number of times of repeatedly applying the transient power (such as 100 cycles);

[0106] Meanwhile, the system automatically checks whether the input parameters exceed the output capacity of the power drive module (such as maximum voltage / current limits) and the safe operating area (SOA) of the device under test. If exceeded, an alarm is prompted and the execution is refused.

[0107] Then, an arbitrary waveform generator (AWG) or a programmable power supply is used to generate waveform signals, supporting a waveform update rate of up to 100 kHz and an accuracy of ≤±0.5% full scale, as follows:

[0108] Pulse-type waveform: A square wave signal is generated according to the overload amplitude, duration, and interval time. Duty cycle = duration / (duration + interval time).

[0109] Step-type waveform: A step voltage / current signal is generated with a rise time ≤1 μs (optimized by the hardware drive circuit), supporting a gradual step (such as a soft start step with a slow rising edge).

[0110] Sine-type waveform: The frequency and amplitude are set to generate a sinusoidal alternating power signal, supporting a frequency sweep mode (frequency linearly changes from 10 Hz to 10 kHz).

[0111] Combined-type waveform: Multiple basic waveforms are spliced in a time series through waveform editing software (such as the first 5 ms pulse + the next 10 ms step), supporting parametric editing of waveform nodes.

[0112] Meanwhile, the output of the waveform generator is connected to a high-precision power meter (such as the Keysight N1913A) to verify whether the parameters of the generated waveform, such as amplitude, frequency, rise / fall time, etc., meet the preset operating conditions. When the error exceeds 1%, it is automatically recalibrated.

[0113] Next, a linear power amplifier or a switching power amplifier is selected (selected according to the power level), and the amplification factor is adjusted according to the rated power of the device under test to ensure that the distortion of the output power waveform <1%; and a fast fuse is connected in series (fusing current = 1.5 times the maximum overload current), and a TVS diode is connected in parallel to protect the device under test from voltage spike impacts; meanwhile, the voltage / current across the device under test is monitored in real time. If a spike exceeding the safety threshold appears (such as the voltage exceeding the rated value by 10%), the power drive module automatically cuts off the output and records the fault waveform.

[0114] Subsequently, the waveform generator and the data acquisition card are connected through a BNC trigger line to ensure that the moment of transient power application is strictly synchronized with the sampling clock of the high-frequency acquisition module (trigger delay ≤100 ns); meanwhile, the control software generates an event sequence according to the preset operating conditions (such as "initial power stable → wait for 5 s → apply transient power → continue for N cycles → restore initial power"), and the switching conditions for each stage are based on sensor feedback signals (such as temperature stable signal, overload time timing completion signal).

[0115] Finally, the applied transient power waveform (superposition of voltage / current waveforms) is displayed in real time through an oscilloscope. By comparing with the preset waveform template, waveform distortion points (such as overshoot at the rising edge and oscillation at the falling edge) are marked; and the output temperature of the power drive module is monitored (through a built-in thermocouple). If the temperature exceeds the safe temperature (such as 80°C), the air-cooled heat dissipation is automatically started and the output power is reduced to 70% of the rated value.

[0116] Meanwhile, in the data acquisition system, a unique identifier (such as timestamp + waveform type code) is added to each transient overload event, and the following data is associated and stored:

[0117] Preset operating condition parameters (amplitude, duration, interval time, etc.);

[0118] Original sampling data of the actual output waveform (voltage / current waveform array);

[0119] Environmental parameters (temperature, humidity, air pressure) at the application moment.

[0120] Step 4: During the application of transient overload power, the temperature, voltage, and current data of the power electronic component under test are collected in real time at a high-frequency sampling rate not lower than 10 kHz, and the sampling time is recorded simultaneously.

[0121] Specifically, first, a 24-bit high-precision data acquisition card (such as NI PCIe-6366 or Keysight 34972A) is selected, which supports at least 3-channel synchronous acquisition (temperature, voltage, current), and the single-channel sampling rate ≥ 50 kHz (meeting the high-frequency requirement above 10 kHz and leaving a margin); a hardware synchronous clock module (such as a 10 MHz oven-controlled crystal oscillator) is configured to ensure that the sampling time deviation of the three channels ≤ 1 μs, meeting the timing consistency requirements of multiple physical quantities during the transient process.

[0122] For temperature signal acquisition, thermocouple sensors and infrared temperature sensors are selected; among them, the mV-level signal output by the thermocouple sensor (such as a K-type thermocouple) is amplified by a signal amplifier (gain 1000 times, noise ≤ 1 μV) and then connected to the analog input channel of the acquisition card, with a built-in cold-junction compensation circuit (accuracy ±0.1°C); the infrared temperature sensor (such as FLIR A35) transmits temperature data in real time through a USB interface and is triggered synchronously with the acquisition card clock (trigger delay ≤ 5 μs).

[0123] For voltage / current signal acquisition, isolated voltage sensors and current sensors are selected. Among them, the isolated voltage sensor (such as LEM LV25-P, bandwidth 100 kHz) outputs a 0-5V voltage signal, which is directly connected to the acquisition card. The current sensor (such as LEM LA25-NP, bandwidth 50 kHz) is converted into a voltage signal through an integrating resistor (1A = 1V), and high-frequency noise is filtered by an anti-aliasing filter (cutoff frequency 20 kHz, third-order Butterworth filter).

[0124] Then, according to the highest frequency component f of the transient power waveform max Calculate the minimum sampling interval Δt to satisfy the Nyquist sampling theorem:

[0125]

[0126] For example, for a pulse waveform with a rise time of 1 μs, f max ≈0.5 / rise time = 500 kHz, then Δt ≤ 1 μs (corresponding to a sampling rate ≥ 1 MHz);

[0127] The system default sampling rate is set to 10 kHz. When f max > 5 kHz is detected, it is automatically increased to 20 kHz or higher;

[0128] At the same time, connect the "output trigger" port of the waveform generator to the "external trigger" port of the acquisition card through the BNC trigger line. When the transient power waveform starts to be output, trigger the acquisition card to start high-frequency sampling; each sampling point is attached with a 64-bit high-precision timestamp (resolution 1 ns), and the timestamp reference is the trigger moment to ensure the strict timing alignment of the data sequence and the power waveform;

[0129] Next, perform real-time data acquisition and monitoring; before triggering, the acquisition card samples the environmental parameters (temperature, humidity) at a low frequency of 1 Hz for 5 seconds to establish the reference environmental data; after triggering, immediately switch to the high-frequency sampling mode (≥ 10 kHz) to synchronously acquire the following data:

[0130] The output voltage of the temperature sensor (converted to a temperature value, resolution 0.01 °C);

[0131] The output voltage of the voltage sensor (resolution 0.1 mV);

[0132] The output voltage of the current sensor (resolution 0.1 mA);

[0133] After the trigger ends, after the transient power is stopped being applied, continue high-frequency sampling for 100 ms (to capture the temperature decay process), and then switch back to low-frequency sampling until the system is on standby;

[0134] Meanwhile, the host computer software (such as LabVIEW) real-time displays the three-channel waveform curves and sets the overload threshold alarm (such as a red mark when the voltage fluctuation exceeds ±5% of the rated value); if the occupancy rate of the acquisition card buffer exceeds 80%, the DMA (Direct Memory Access) mode is automatically enabled to store the data in the SSD hard disk in real time (write speed ≥ 500MB / s) to avoid data loss; when the sampling rate fluctuation is detected to exceed ±5%, the clock source is automatically recalibrated, and the abnormal data segment before calibration is discarded;

[0135] Finally, the collected raw data is stored in binary format, and each data frame contains:

[0136] Timestamp (12 bytes, UTC time + nanosecond offset);

[0137] Temperature value (4 bytes, single-precision floating-point type);

[0138] Voltage value (4 bytes, single-precision floating-point type);

[0139] Current value (4 bytes, single-precision floating-point type);

[0140] Channel status flag bit (1 byte, indicating whether the sensor connection is normal);

[0141] Meanwhile, a unique ID (such as "20250429-001") is generated for each test case, and the associated operating condition parameter file (.xml format, including waveform type, sampling rate, trigger time, etc.) is stored;

[0142] In addition, the sensor cable uses double-shielded twisted pair (the shielding layer is grounded), and the distance from the power drive module cable is ≥ 30cm to reduce electromagnetic coupling interference; the power supply port of the acquisition card is connected to an EMI filter (attenuating noise of 10kHz - 10MHz ≥ 30dB), and the overall grounding resistance of the chassis is ≤ 0.1Ω to form a complete grounding loop.

[0143] Step Five: Preprocess the collected temperature, voltage, and current data, remove noise and outliers, and perform time synchronization calibration;

[0144] Specifically, first, extract the timestamp information of the three-channel data, and uniformly convert the sampling times of temperature, voltage, and current into relative time (unit: μs) with the "starting moment of transient power application" as the origin to eliminate the reference difference caused by the clock drift of different sensors; for asynchronous sampling sensors (such as infrared temperature sensors transmitted through USB), establish a time mapping relationship through the hardware trigger signal (BNC trigger in Step Four), and interpolate the asynchronous data into the synchronous time grid (such as a 100μs interval corresponding to a 10kHz sampling rate);

[0145] For the voltage / current sensor (hardware synchronous acquisition card) and the temperature sensor (with a delay of ±5 μs), find the two nearest sampling points on the time axis, and calculate the value at the target time point through linear interpolation. The formula is:

[0146]

[0147] where \(t_1\leq t\leq t_2\), and \(t_2 - t_1\leq2\Delta t\) (\(\Delta t\) is the sampling interval);

[0148] Calculate the cross-correlation coefficient of the three-channel data after calibration. It is required that the correlation coefficient between the voltage-current signal is > 0.99, and the time delay between the temperature signal and the power signal (\(V\times I\)) is < 5 μs;

[0149] Then, perform filtering on the collected temperature, voltage, and current data to remove noise; specifically as follows:

[0150] Temperature signal (low-frequency slow-varying signal): Use a 5th-order Butterworth low-pass filter (cutoff frequency 1 kHz) to filter out high-frequency electromagnetic interference (such as switching noise generated by the power drive module); superimpose moving average filtering (window size 10 sampling points, corresponding to 1 ms) to smooth the random fluctuations of the temperature curve;

[0151] Voltage / current signal (high-frequency dynamic signal): For the spike noise of pulse-type overload, use an adaptive median filter (the window size is dynamically adjusted with the rising edge of the waveform. For example, when the rising edge is 1 μs, the window is set to 3 sampling points); for the harmonic interference of the sine-type waveform, use an IIR notch filter (the center frequency is an integer multiple of the fundamental frequency, such as 50 Hz, 100 Hz notch);

[0152] At the same time, automatically switch the filtering strategy according to the type of transient power waveform, specifically as follows:

[0153] Pulse-type waveform: Enable the high-frequency noise suppression mode (cutoff frequency is set to 5 times the waveform frequency);

[0154] Step-type waveform: Enable edge-preserving filtering (to avoid blurring of the step edge, such as bilateral filtering);

[0155] Real-time monitor the main frequency of the noise through signal spectrum analysis (FFT transformation), and dynamically adjust the filter parameters (such as updating the cutoff frequency every 10 ms);

[0156] Next, use the 3σ criterion and the local outlier factor (LOF) to detect and repair outliers in the collected temperature, voltage, and current data; specifically as follows:

[0157] 3σ criterion: Calculate the mean μ and standard deviation σ of the data for each channel, and mark the data points that deviate from the mean by more than 3σ as anomalies (e.g., temperature sudden change exceeding ±5°C, voltage / current fluctuation exceeding ±10% of the rated value);

[0158] LOF: For non-normally distributed data, calculate the local density of each data point, and determine it as an anomaly point when the LOF value > 2 (applicable to sudden interferences in complex overload scenarios);

[0159] Among them, the outlier repair strategies include neighborhood interpolation repair and physical constraint verification; specifically as follows:

[0160] Neighborhood interpolation repair: Replace the outlier with the weighted average of the 5 normal data points before and after the outlier point (weight of the nearest neighbor point is 0.8, the next nearest neighbor is 0.1, and so on);

[0161] Physical constraint verification: Repair contradictory data according to the physical meaning of thermal resistance. For example, when the temperature rises, the power must be positive. If a negative power outlier point appears, it is forced to be set to 95% of the power value at the previous moment (to avoid logical errors);

[0162] Finally, perform normalization processing and format conversion on the collected temperature, voltage, and current data; specifically as follows:

[0163] Convert the output voltage (0 - 5V) of the voltage / current sensor to the actual physical quantity (voltage: V, current: A), and convert the mV signal of the temperature sensor to the temperature value (°C), with the precision reserved to three decimal places;

[0164] Perform normalization processing on the data (such as Z-score standardization) to facilitate subsequent calculation of the thermal resistance model. The formula is:

[0165]

[0166] Among them, μ and σ are the mean and standard deviation of the data for this channel.

[0167] Step 6: Based on the transient thermal resistance model, combine the preprocessed temperature, voltage, and current data to calculate the transient thermal resistance of the measured power electronic component at different moments during the transient overload process;

[0168] Specifically, first, select a suitable transient thermal resistance model according to the physical structure and heat dissipation characteristics of the measured power electronic component; for components with relatively simple structures and relatively uniform heat distributions, the lumped parameter model is preferably used; for components with complex structures and non-uniform heat distributions, the distributed parameter model is adopted; the lumped parameter model usually equivalent the component to one or more thermal resistance-capacitance networks and describes its thermal characteristics through a finite number of nodes; the distributed parameter model is based on the heat transfer partial differential equation and considers the temperature distribution and heat conduction process inside the component;

[0169] Meanwhile, collect the physical structure parameters of the power electronic component under test, such as size, shape, material properties, etc., as well as the thermal physical properties parameters such as the thermal conductivity of the material; calibrate the model parameters according to the actual working environment and boundary conditions of the component; for example, for components with air-cooled heat dissipation, consider the convective heat transfer coefficient of air; for components with water-cooled heat dissipation, consider factors such as the flow rate and temperature of the coolant; the parameter calibration can be carried out by combining experimental tests and numerical simulations; first, conduct a steady-state thermal test, measure the stable temperature of the component at different powers, and use this data to preliminarily calibrate the thermal resistance parameters of the model; then conduct a transient thermal test, and further optimize the model parameters by comparing the model prediction results with the actual measurement data.

[0170] Then, extract the voltage value V(t) and current value I(t) at each sampling moment from the preprocessed voltage and current data.

[0171] According to the definition of power:

[0172] P(t) = V(t) × I(t);

[0173] Calculate the instantaneous power P(t) at each sampling moment.

[0174] Next, determine the initial temperature T0 (i.e., the initial temperature recorded in step two) from the preprocessed temperature data.

[0175] Calculate the temperature change at each sampling moment:

[0176] ΔT(t) = T(t) - T0;

[0177] where T(t) is the temperature value at this moment.

[0178] For the lumped parameter model, according to the definition of thermal resistance:

[0179]

[0180] Calculate the transient thermal resistance R th (t);

[0181] For the distributed parameter model, it is necessary to numerically solve the heat transfer partial differential equation to obtain the temperature distribution inside the component; then, according to the definition of thermal resistance, calculate the transient thermal resistance at different positions or overall; usually, numerical methods such as the finite difference method and the finite element method are used for solving; during the calculation process, use the calibrated model parameters and the calculated power P(t) as input conditions.

[0182] Finally, smooth the calculated transient thermal resistance data to remove possible noise and fluctuations; methods such as moving average filtering and Savitzky-Golay filtering can be used; at the same time, analyze the change trend of the transient thermal resistance, for example, judge whether the thermal resistance increases with the increase of the overload time and whether there are peaks; and associate the calculated transient thermal resistance data with the corresponding sampling time, power, temperature and other data, and store them in a database or file for subsequent analysis and evaluation; storage can be in formats such as Excel and CSV, or a professional database management system can be used.

[0183] Step 7: According to the evaluation index, analyze the change curve of the transient thermal resistance, evaluate the transient overload performance of the measured power electronic component, and generate an evaluation report;

[0184] Specifically, by extracting core indicators such as the transient thermal resistance peak value, peak time, thermal resistance recovery time and change stability, and combining the coupled analysis of the preprocessed thermal resistance curve and the power waveform, evaluate the thermal characteristics of the measured component under transient overload; first, calculate the thermal resistance value at each moment based on the heat transfer model, generate a time-thermal resistance curve and superimpose the power waveform, and mark key features such as the peak point and the end point of the recovery time; then compare the measured indicators with the design thresholds (such as JEDEC standards) to determine the performance level (qualified / warning / unqualified), identify abnormal features such as thermal resistance oscillation and non-monotonic changes and trigger retesting; finally, automatically generate a standardized evaluation report including test data, curve analysis, conclusions and suggestions, support PDF export and data traceability, provide a quantitative basis for component reliability analysis and heat dissipation design optimization, and achieve a complete closed-loop from data processing to engineering application.

[0185] In one embodiment, specifically: in Step 4, the high-frequency sampling rate is dynamically adjusted according to the thermal time constant of the measured power electronic component, and the sampling interval satisfies the formula:

[0186]

[0187] where f max is the highest frequency component of the transient power waveform;

[0188] Specifically, assuming that the highest frequency component f max of the transient power waveform is 10 kHz, the sampling interval can be calculated according to the formula:

[0189]

[0190] Then the sampling rate should be at least:

[0191]

[0192] Such a sampling rate can ensure that under the action of this transient power waveform, the sampling of the relevant parameters of the component is sufficient and no important information will be lost. At the same time, if the thermal time constant of the device under test is small, its temperature may change faster. In this case, the sampling rate can be further increased according to the thermal time constant to better capture the rapid temperature change.

[0193] In one embodiment, specifically: in step three, the transient power waveform includes a pulse type, a step type, a sine type, or a combination of any two or more waveforms;

[0194] Among them, the pulse type waveform presents a periodic or non-periodic pulse shape; within one pulse period, the power will rapidly rise to a relatively high value (overload power) in a short time and then quickly drop to a lower level. For example, during the operation of some switching power supplies, a similar pulse power will appear, which can simulate the instantaneous high-power impact that power electronic components receive during actual operation. Parameters such as the width of the pulse (i.e., the overload duration), the amplitude (overload amplitude), and the frequency of the pulse (related to the overload interval time) can all be adjusted according to specific test requirements;

[0195] The step type waveform shows that the power instantaneously jumps from a stable initial value to a relatively high overload value and remains at this overload value for a period of time, and then suddenly drops back to the initial value or other stable values. This waveform is often used to simulate the power change of components under conditions such as startup and load mutation. For example, when a certain load in the power system is suddenly connected or disconnected, the power change that the relevant power electronic components bear is similar to the step type;

[0196] The sine type transient power waveform is a power signal that changes according to the sine function law, and its power value periodically changes between the maximum value and the minimum value. This waveform can simulate the power fluctuations caused by factors such as voltage fluctuations and harmonics in some AC power supply systems. For example, in some variable frequency speed regulation systems, the frequency and amplitude of the power supply will change, generating a power fluctuation similar to the sine type. Through the sine type transient power waveform test, the thermal performance of components under this working condition can be evaluated;

[0197] The combination of any two or more waveforms. In an actual power electronic system, the power change that components bear is often complex and diverse, and may simultaneously include various different types of power fluctuations. Therefore, it is allowed to combine waveforms such as pulse type, step type, and sine type, which can more realistically simulate various extreme or complex working conditions that components may encounter during actual operation. For example, first apply a step type power increase, and then immediately superimpose a series of pulse type power fluctuations at this high power level. Such a combined waveform can more comprehensively test the thermal resistance transient overload performance of components.

[0198] The preset transient overload conditions include different overload amplitudes, overload durations, and overload intervals;

[0199] Among them, the overload amplitude refers to the multiple of increase or the specific increased value of the transient power relative to the power (such as the rated power) when the measured power electronic component is operating normally; for example, an overload amplitude of 2 times the rated power means that during the transient process, the power borne by the component is twice its rated power; the setting of the overload amplitude can be determined according to the possible overload situations in the actual application scenario. Different overload amplitudes will have different degrees of influence on the thermal performance of the component. By testing the change of thermal resistance under different overload amplitudes, the bearing capacity of the component under different overload degrees can be understood;

[0200] The overload duration refers to the length of time during which the transient power remains at the overload level; the length of the overload duration will affect the heating degree and heat accumulation of the component; generally speaking, the longer the overload duration, the more heat the component generates and the higher the temperature rises; for example, an overload lasting 10 milliseconds and an overload lasting 100 milliseconds have very different effects on the thermal performance of the component; by setting different overload durations, the performance of the component under the continuous action of different thermal stresses can be tested;

[0201] The overload interval refers to the time interval between two adjacent overloads; this parameter determines how much time the component has for heat dissipation and recovery between two overloads; for example, in some power electronic devices with intermittent operation, the component will periodically bear overloads, and the length of the overload interval will affect the temperature fluctuation and long-term reliability of the component; reasonably setting the overload interval can simulate the periodic thermal stress situation in actual operation and evaluate the thermal performance and life of the component under this condition.

[0202] In one embodiment, specifically: in step six, the transient thermal resistance model is a lumped parameter model or a distributed parameter model established based on the heat transfer principle;

[0203] Among them, the lumped parameter model regards the entire power electronic component as a whole, ignores the internal temperature difference, and represents the thermal characteristics of the component concentratedly by one or several thermal resistances and heat capacities; it is applicable to the situation where the internal temperature distribution of the component is relatively uniform, or the internal heat conduction speed is very fast, so that the temperature can be considered to be the same in a short time; for example, for some small and simple-structured electronic chips, the lumped parameter model can be used to analyze their thermal behavior, which can simplify the calculation process and quickly obtain the change of thermal resistance with time;

[0204] The distributed parameter model takes into account the non-uniform temperature distribution inside the component; it divides the component into multiple small units, each unit having its own thermal resistance, heat capacity and other parameters, and describes the temperature changes of each unit by solving the heat transfer equation, thereby obtaining the thermal characteristics of the entire component; for large and structurally complex power electronic components, such as power modules, due to the obvious temperature gradient inside them, the distributed parameter model can more accurately reflect their real thermal behavior, but the calculation is relatively complex and requires more computing resources and time;

[0205] The parameters of the thermal resistance transient model are calibrated by the physical structure parameters, material thermal conductivity and boundary conditions of the measured power electronic component;

[0206] Among them, the physical structure parameters include the size (such as length, width, thickness, etc.), shape (such as square, circular, etc.) and internal structure (such as the number of chip layers, packaging form, etc.) of the measured power electronic component; these parameters will affect the heat conduction path and speed inside the component, thereby affecting the thermal resistance; for example, for a component with a larger thickness, the time required for heat to conduct to the surface will be longer, and its thermal resistance will increase accordingly;

[0207] The material thermal conductivity is a physical quantity that measures the ability of a material to conduct heat, and the thermal conductivities of different materials vary greatly; in the thermal resistance transient model, the thermal conductivity of the material is a key parameter, which determines the speed of heat conduction inside the material; for example, the thermal conductivity of copper is much higher than that of plastic, so under the same conditions, a copper heat sink can conduct heat faster and reduce the temperature of the component; by accurately obtaining the thermal conductivities of each part of the component material and incorporating them into the model parameters, the model can more accurately reflect the actual heat conduction process;

[0208] The boundary conditions mainly refer to the heat exchange situation between the component and the surrounding environment, including the ambient temperature, convective heat transfer coefficient (reflecting the heat exchange ability between air or other fluids and the surface of the component), radiation conditions, etc.; these factors will affect the heat dissipation speed of the component, and thus affect the thermal resistance; for example, in a forced air cooling environment, the convective heat transfer coefficient is large, the heat dissipation speed of the component is accelerated, and the thermal resistance will decrease; by reasonably setting the boundary condition parameters, the thermal resistance transient model can better conform to the actual working environment and improve the accuracy of the model.

[0209] In one embodiment, specifically: in step two, the formula for calculating the initial thermal resistance is:

[0210]

[0211] Where T initial is the initial temperature, T ambient is the ambient temperature, and P initial is the initial constant power;

[0212] Specifically, assume that an initial constant power of 50 W (50% of the rated power) is applied for 30 minutes until the temperature stabilizes (the fluctuation of 10 consecutive samples ≤ ±0.5 °C for 15 minutes); the initial temperature is 45.0 °C (average of the last 5 minutes); the voltage is 10.02 V, and the current is 4.99 A. Calculate P initial = 10.02 × 4.99 ≈ 50.0 W;

[0213] According to the initial thermal resistance calculation formula:

[0214]

[0215] In one embodiment, specifically: in step one, the test platform includes a test fixture, a power driving module, a temperature sensor, a voltage sensor, and a current sensor;

[0216] The test fixture is used to fix the power electronic component under test;

[0217] Specifically, the test fixture adopts an aluminum alloy or copper heat-conducting base (thickness ≥ 5 mm), with a nickel-plated surface treatment to enhance oxidation resistance. The base is fixed on the test platform frame through insulating supports (such as ceramic pillars) to ensure electrical isolation between the component under test and the platform body; the fixture is equipped with an elastic pressing piece with adjustable pressure (such as a spring-loaded pressing piece) to closely attach the power electronic component under test (such as an IGBT module, MOSFET chip) to the heat-conducting base, and the contact pressure is controlled at 5 - 10 N / cm 2 , ensuring a low contact thermal resistance (≤ 0.1 °C·W) of the heat conduction path; at the same time, a high thermal conductivity silicone (thermal conductivity ≥ 5 W / (m·K)) is coated between the component and the fixture base, filling the gap to 0.05 - 0.1 mm to improve the surface fit; for scenarios where electrical isolation is required, an aluminum nitride ceramic insulating sheet (thickness 0.2 mm, thermal conductivity 170 W / (m·K)) is installed between the component and the fixture to balance the insulation requirements and thermal conductivity efficiency.

[0218] The temperature sensor is attached to the surface or key heat-generating area of the power electronic component under test and is connected to the power driving module, voltage sensor, and current sensor;

[0219] Among them, the temperature sensor uses a K-type thermocouple (accuracy ±0.5°C, response time ≤20 ms). The probe is pasted on the center position of the component surface (for chip-level devices) or the substrate welding point (for module-level devices) through thermal conductive silicone to ensure that the measurement point is the key heat generation area. The sensor lead uses a double-layer shielded wire (the shield layer is grounded), with a length ≤30 cm, to reduce the influence of electromagnetic interference on the temperature signal. The mV signal output by the thermocouple is amplified by a signal conditioning module (gain 1000 times, noise ≤1 μV) and then connected to the analog input channel of a data acquisition card (such as NI USB-6366), and synchronously sampled with the power signal (trigger delay ≤10 μs).

[0220] The power drive module integrates a waveform generator and a power amplifier. The waveform generator (such as Keysight 33522B) supports generating basic waveforms such as pulses (rise time ≤1 μs), steps (overshoot ≤5%), and sine waves (distortion ≤0.1%), as well as custom combined waveforms (importing CSV waveform data through host computer software). The power amplifier (such as AMETEK 2150A) is selected according to the rated power of the device under test (output range 0-200 W, accuracy ±0.5%). It has an internal current / voltage double closed-loop feedback to ensure the stability of power output. The output end of the power drive module is connected to the pins of the device under test through a silver-plated copper wire (cross-sectional area ≥1 mm 2 , impedance ≤0.01 Ω), and a current sensor (such as LEM LA55-P) is connected in series, and a voltage sensor (such as LEM LV20-P) is connected in parallel to form a "power application - real-time monitoring" closed loop.

[0221] The voltage sensor and the current sensor are respectively used to collect the voltage across and the current flowing through the power electronic component under test.

[0222] Among them, the voltage sensor uses an isolated Hall voltage sensor (such as LEM LV25-P, bandwidth DC-100 kHz). The primary side is connected in parallel across the device under test, and the secondary side outputs a 0-5V voltage signal (1V corresponds to a rated voltage of 100V) to achieve electrical isolation between the high-voltage circuit and the low-voltage acquisition system (isolation voltage ≥2.5 kV).

[0223] The current sensor uses a closed-loop Hall current sensor (such as LEM LA28-NP, bandwidth DC-50 kHz). The primary side is connected in series in the main circuit, and the secondary side is converted into a voltage signal through a 1Ω sampling resistor (1A = 1V), supporting bidirectional current measurement (overload capacity 200% of the rated current).

[0224] In one embodiment, specifically: in step seven, the evaluation indicators include the peak value of the transient thermal resistance, the time to reach the peak value, the thermal resistance recovery time, and the stability of the thermal resistance change.

[0225] Specifically, the peak transient thermal resistance refers to extracting the maximum value from the transient thermal resistance curve, corresponding to the highest thermal resistance state of the component during overload, and reflecting its short-term heat dissipation limit ability;

[0226] The thermal resistance recovery time is defined as the time required for the thermal resistance to drop from the peak to "steady-state reference thermal resistance + 10% initial thermal resistance", reflecting the heat dissipation efficiency of the component after overload ends;

[0227] The thermal resistance change stability refers to calculating the standard deviation or coefficient of variation of the thermal resistance curve during the transient process to evaluate the amplitude of thermal resistance fluctuation. The smaller the value, the better the stability.

[0228] The evaluation report includes test data, test curves, and test conclusions;

[0229] Among them, the test data provides quantitative support to ensure the traceability of the evaluation process; the test curve reveals the dynamic coupling relationship between thermal resistance and power through visualization means, facilitating the rapid positioning of abnormal characteristics; the test conclusion transforms technical indicators into engineering judgments, providing direct basis for component selection, heat dissipation design optimization, and reliability certification.

[0230] In summary, a method for testing the transient overload of the thermal resistance of power electronic components provided by an embodiment of the present invention includes building a test platform and calibrating the environment, applying an initial constant power to calculate the initial thermal resistance, generating and applying a transient power waveform according to a preset working condition, collecting data at a high-frequency sampling rate not lower than 10 kHz, preprocessing the collected data and then calculating the transient thermal resistance in combination with a transient thermal resistance model, and finally analyzing the curve according to evaluation indicators and generating a report; this method can accurately simulate actual complex overload working conditions, effectively solve the problems of insufficient traditional test accuracy, lack of real-time dynamic monitoring ability, and poor adaptability to complex overload scenarios, and provides a reliable and efficient solution for the evaluation of the transient overload performance of power electronic components.

[0231] Figure 2 It is a schematic diagram of the functional modules of a system for testing the transient overload of the thermal resistance of power electronic components according to an embodiment of the present application. As Figure 2 shown, a system for testing the transient overload of the thermal resistance of power electronic components includes: a test platform building module, a steady-state reference test module, a transient power generation module, a high-frequency synchronous acquisition module, a data preprocessing module, a transient thermal resistance calculation module, and a performance evaluation report module;

[0232] The test platform building module is configured to build a test platform and initialize and calibrate the test environment. The test platform integrates a power drive module;

[0233] A steady-state benchmark testing module, configured to apply an initial constant power to the power electronic component under test through a power driving module. After the temperature of the power electronic component under test stabilizes, record the initial temperature, initial voltage, and initial current at this time, and calculate the initial thermal resistance;

[0234] A transient power generation module, configured to generate a corresponding transient power waveform according to a preset transient overload condition, and apply a transient overload power to the power electronic component under test through the power driving module according to this transient power waveform;

[0235] A high-frequency synchronous acquisition module, configured to, during the application of the transient overload power, collect the temperature, voltage, and current data of the power electronic component under test in real time at a high sampling rate not lower than 10 kHz, and record the sampling time at the same time;

[0236] A data preprocessing module, configured to preprocess the collected temperature, voltage, and current data, remove noise and outliers, and perform time synchronization calibration;

[0237] A transient thermal resistance calculation module, configured to calculate the transient thermal resistance of the power electronic component under test at different moments during the transient overload process based on a thermal resistance transient model and in combination with the preprocessed temperature, voltage, and current data;

[0238] A performance evaluation report module, configured to analyze the change curve of the transient thermal resistance according to the evaluation index, evaluate the transient overload performance of the thermal resistance of the power electronic component under test, and generate an evaluation report.

[0239] In one embodiment, specifically: The test platform building module integrates a power driving module, and the power driving module includes a waveform generator and a power amplifier;

[0240] The waveform generator is configured to generate a pulse-type, step-type, sine-type, or combined-type transient power waveform;

[0241] The power amplifier is configured to amplify the waveform signal to the rated power range of the component under test and apply a transient overload power.

[0242] In one embodiment, specifically: The data preprocessing module includes a preprocessing unit and a thermal resistance calculation unit;

[0243] The preprocessing unit is configured to perform noise suppression and outlier rejection using a digital filtering algorithm and the 3σ criterion, and perform multi-sensor data time synchronization through hardware triggering or software interpolation;

[0244] The thermal resistance calculation unit is configured to call a lumped parameter model or a distributed parameter model, calibrate the model parameters in combination with the physical structure parameters of the component under test, the thermal conductivity of the material, and the boundary conditions, and calculate the transient thermal resistance value in real time.

[0245] In summary, the transient thermal resistance overload test system for power electronic components provided by the embodiments of the present invention realizes the automation of the test process, reduces manual intervention, and improves the test efficiency and the accuracy and stability of data processing by designing a highly integrated test system covering multiple functional modules such as test platform construction, steady-state reference test, and transient power generation, and through the collaborative work among the modules.

[0246] For other details of the technical solutions implemented by each module in the transient thermal resistance overload test system for power electronic components in the above embodiments, reference can be made to the description in the method for testing the transient thermal resistance overload of power electronic components in the above embodiments, and details are not described herein again.

[0247] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other. For system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments.

[0248] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations. It cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the specific details disclosed above are only for the purpose of illustration and easy understanding, rather than limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details for implementation.

[0249] In the present disclosure, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The block diagrams of devices, apparatuses, equipment, and systems involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used herein refer to the word "and / or", and can be used interchangeably with it, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0250] In addition, as used herein, "or" as used in a list of items beginning with "at least one" indicates a disjunctive list such that, for example, a listing of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Further, the phrase "exemplary" does not mean that the examples described are preferred or better than other examples.

[0251] It should also be noted that in the systems and methods of the present disclosure, the various components or steps may be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present disclosure.

[0252] Various changes, substitutions, and alterations to the techniques described herein may be made without departing from the teachings of the technology defined by the appended claims. In addition, the scope of the claims of the present disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and acts described above. Current or later-developed processes, machines, manufactures, compositions of events, means, methods, or acts that perform substantially the same function or achieve substantially the same result as the corresponding aspects described herein may be utilized. Accordingly, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or acts within their scope.

[0253] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0254] The above description has been presented for purposes of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize some of their variations, modifications, alterations, additions, and subcombinations.

Claims

1. A transient overload test method for the thermal resistance of power electronic components, characterized in that, It includes the following steps: Build a test platform and perform initial calibration on the test environment. The test platform integrates a power drive module; Apply an initial constant power to the power electronic component under test through the power drive module. After the temperature of the power electronic component under test stabilizes, record the initial temperature, initial voltage, and initial current at this time, and calculate the initial thermal resistance; Generate a corresponding transient power waveform according to the preset transient overload condition, and apply the transient overload power to the power electronic component under test through the power drive module according to this transient power waveform; During the application of the transient overload power, collect the temperature, voltage, and current data of the power electronic component under test in real time at a high-frequency sampling rate not lower than 10 kHz, and record the sampling time at the same time; Preprocess the collected temperature, voltage, and current data to remove noise and outliers, and perform time synchronization calibration; Based on the transient thermal resistance model, combine the preprocessed temperature, voltage, and current data to calculate the transient thermal resistance of the power electronic component under test at different moments during the transient overload process; According to the evaluation index, analyze the change curve of the transient thermal resistance, evaluate the transient thermal resistance overload performance of the power electronic component under test, and generate an evaluation report.

2. A transient overload test method for the thermal resistance of power electronic components according to claim 1, characterized in that: The high-frequency sampling rate is dynamically adjusted according to the thermal time constant of the power electronic component under test, and the sampling interval satisfies the formula: where f max is the highest frequency component of the transient power waveform.

3. A transient overload test method for the thermal resistance of power electronic components according to claim 1, characterized in that: The transient power waveform includes pulse type, step type, sine type, or a combination of any two or more waveforms. The preset transient overload conditions include different overload amplitudes, overload durations, and overload interval times.

4. A transient overload test method for the thermal resistance of a power electronic component according to claim 1, characterized in that: The transient thermal resistance model is a lumped parameter model or a distributed parameter model established based on the heat transfer principle. The parameters of the transient thermal resistance model are calibrated through the physical structure parameters, material thermal conductivity, and boundary conditions of the power electronic component under test.

5. A transient overload test method for the thermal resistance of a power electronic component according to claim 1, characterized in that: The formula for calculating the initial thermal resistance is: Among them, T initial is the initial temperature, T ambient is the ambient temperature, and P initial is the initial constant power.

6. A transient overload test method for the thermal resistance of a power electronic component according to claim 1, characterized in that: The test platform includes a test fixture, a temperature sensor, a voltage sensor, and a current sensor; The test fixture is used to fix the power electronic component under test; The temperature sensor is attached to the surface or key heat generation area of the power electronic component under test and is connected to the power drive module, voltage sensor, and current sensor; The voltage sensor and current sensor are respectively used to collect the voltage across and the current flowing through the power electronic component under test.

7. A transient overload test method for the thermal resistance of a power electronic component according to claim 1, characterized in that: The evaluation index includes the peak value of the transient thermal resistance, the time to reach the peak value, the thermal resistance recovery time, and the stability of the thermal resistance change; the evaluation report includes test data, test curves, and test conclusions.

8. A transient overload test system for power electronic components, which is applied to a transient overload test method for power electronic components according to any one of claims 1-7, characterized in that, The system includes: a test platform building module, a steady-state benchmark test module, a transient power generation module, a high-frequency synchronous acquisition module, a data preprocessing module, a transient thermal resistance calculation module, and a performance evaluation report module; The test platform building module is configured to build a test platform and perform initial calibration on the test environment. The test platform integrates a power drive module; The steady-state benchmark test module is configured to apply an initial constant power to the power electronic component under test through the power drive module. After the temperature of the power electronic component under test stabilizes, record the initial temperature, initial voltage, and initial current at this time, and calculate the initial thermal resistance; The transient power generation module is configured to generate a corresponding transient power waveform according to a preset transient overload condition, and apply a transient overload power to the power electronic component under test according to the transient power waveform through the power driving module; The high-frequency synchronous acquisition module is configured to, during the application of the transient overload power, collect the temperature, voltage and current data of the power electronic component under test in real time at a high sampling rate not lower than 10 kHz, and record the sampling time at the same time; The data preprocessing module is configured to preprocess the collected temperature, voltage and current data, remove noise and outliers, and perform time synchronization calibration; The transient thermal resistance calculation module is configured to calculate the transient thermal resistance of the power electronic component under test at different moments during the transient overload process based on the transient thermal resistance model and in combination with the preprocessed temperature, voltage and current data; The performance evaluation report module is configured to analyze the change curve of the transient thermal resistance according to the evaluation index, evaluate the transient overload performance of the thermal resistance of the power electronic component under test, and generate an evaluation report.

9. A transient overload test system for the thermal resistance of power electronic components according to claim 8, characterized in that: The test platform building module integrates the power driving module, and the power driving module includes a waveform generator and a power amplifier; The waveform generator is configured to generate a pulse-type, step-type, sine-type or combined-type transient power waveform; The power amplifier is configured to amplify the waveform signal to the rated power range of the component under test and apply a transient overload power.

10. A transient overload test system for the thermal resistance of power electronic components according to claim 8, characterized in that: The data preprocessing module includes a preprocessing unit and a thermal resistance calculation unit; The preprocessing unit is configured to perform noise suppression and outlier rejection by using a digital filtering algorithm and the 3σ criterion, and perform multi-sensor data time synchronization through hardware triggering or software interpolation; The thermal resistance calculation unit is configured to call a lumped parameter model or a distributed parameter model, calibrate the model parameters in combination with the physical structure parameters of the component under test, the thermal conductivity of the material and the boundary conditions, and calculate the transient thermal resistance value in real time.

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