A test system and method for power electronic devices in extreme irradiation scenarios

Abstract

The application provides a test system and method for power electronic devices in extreme irradiation scenes, the system comprises: a current measurement module, comprising a plurality of parallel resistance paths, which converts real-time current flowing through the power electronic device to be tested into a voltage signal; a current judgment module, which compares the voltage signal with a set voltage threshold, and outputs a first control signal when the voltage signal exceeds the set voltage threshold; a circuit delay module, which receives the first control signal and starts counting, and outputs a second control signal when the duration of the first control signal reaches a preset delay parameter; a circuit selection module, which receives the second control signal and performs logical decoding to generate a path selection instruction, controls the conduction state of each resistance path in the current measurement module, adjusts the current flowing through the power electronic device to be tested, and limits the real-time current to a preset level; and an interactive control module, which is used for setting parameters in the test process and resetting the state of the test system.

Description

Technical Field

[0001] This invention belongs to the field of circuit protection technology, specifically relating to a testing system and method for power electronic devices under extreme irradiation conditions. Background Technology

[0002] Power electronic devices possess high voltage and high current carrying capacity, along with low conduction losses, high switching speeds, and strong surge immunity, enabling efficient power conversion and control. As core components in power electronics, radio frequency power amplification, and harsh environment applications, the performance and reliability of power electronic devices directly determine the operating efficiency, size, cost, and service life of end-user equipment. However, applications of power electronic devices in extreme environments, such as aerospace and nuclear industries, face reliability challenges related to space radiation damage and performance degradation, requiring further research into their radiation failure mechanisms.

[0003] Traditional power device irradiation experiments are conducted using devices such as neutron sources, proton sources, heavy ion sources, and voltage source meters, which are costly. When a power device is irradiated under high pressure and a large number of charge carriers are induced to be generated, it will cause the device to break down, manifested as a sudden increase in the current passing through the device. On the one hand, the current limit of the circuit needs to be set by the voltage source meter; on the other hand, when the circuit current reaches the current limit of the voltage source meter, the current will remain unchanged at that value.

[0004] Traditional irradiation measurement methods can easily damage power devices directly within a short period, making it impossible to study the intermediate processes and mechanisms of irradiation damage. Power devices currently exhibit significant inconsistencies, with different devices having different breakdown current values. However, the current limit of the voltage source meter is limited to a fixed value, constraining the current limits of different devices to the same upper limit, thus preventing the analysis of the actual breakdown current levels of different devices. When the circuit current reaches the voltage source meter's current limit, the current will remain constant at that value, failing to automatically limit the current to a lower level, leading to destructive burnout of the device and hindering the analysis of irradiation damage mechanisms. By the time the testers observe device breakdown and then turn off the voltage source meter, a considerable amount of time has often passed, making it difficult to obtain the device at the transient breakdown stage, study the intermediate processes, waste experimental equipment, and fail to meet the expected experimental needs. Summary of the Invention

[0005] This invention proposes a testing system and method for power electronic devices under extreme irradiation scenarios, which solves the problem that traditional irradiation measurement methods can easily damage power devices directly in a short time and cannot study the intermediate process of irradiation damage.

[0006] To address the aforementioned technical problems, this invention provides a testing system for power electronic devices under extreme irradiation conditions, comprising: a current measurement module, a current judgment module, a circuit delay module, a circuit selection module, and an interactive control module;

[0007] The current measurement module includes multiple parallel resistor paths for converting the real-time current flowing through the power electronic device under test into a voltage signal.

[0008] The current judgment module compares the voltage signal with a set voltage threshold, and outputs a first control signal when the voltage signal exceeds the set voltage threshold.

[0009] The input terminal of the circuit delay module receives the first control signal and starts counting. When the duration of the first control signal reaches a preset delay parameter, the second control signal is output.

[0010] The circuit selection module receives the second control signal and performs logic decoding to generate a path selection instruction, which controls the conduction state of each resistor path in the current measurement module, adjusts the current flowing through the power electronic device under test, and limits the real-time current to a preset level.

[0011] The interactive control module is used to set parameters during the testing process and reset the state of the testing system.

[0012] Preferably, the current measurement module includes a current sampling module, a first switch control module, and a current limiting module;

[0013] The current sampling module includes a sampling resistor and an oscilloscope probe. The sampling resistor is connected in series in the main circuit of the power electronic device under test, and the oscilloscope probe is used to acquire the voltage difference across the sampling resistor.

[0014] The first switch control module includes multiple metal-oxide-semiconductor field-effect transistors (MOSFETs), each MOSFET being connected in series in a corresponding resistor path;

[0015] The current limiting module includes multiple current limiting resistors with different resistance values. The current limiting resistors are connected in series with the MOSFET to form multiple parallel resistor paths.

[0016] Preferably, the current judgment module includes a second switch control module, a voltage threshold setting module, a judgment module, and a circuit protection module;

[0017] The second switch control module includes a metal-oxide-semiconductor field-effect transistor (MOSFET) for controlling the opening and closing of the corresponding path, and for withstanding a high voltage when the path is turned off, thereby limiting the current flowing through the power electronic device under test.

[0018] The voltage threshold setting module includes a regulated power supply and a voltage divider resistor network, used to provide multiple voltage threshold gradients and set multiple current judgment intervals;

[0019] The judgment module includes multiple high-speed comparators. The non-inverting input of the high-speed comparator receives a voltage signal from the current measurement module, and the inverting input receives the voltage threshold. When the voltage signal exceeds the set voltage threshold, the first control signal corresponding to different current ranges is output.

[0020] The circuit protection module includes a clamping diode connected to the input terminal of the high-speed comparator, which is used to limit the voltage amplitude input to the high-speed comparator from exceeding the rated operating voltage of the high-speed comparator.

[0021] Preferably, the circuit delay module includes a counting module and a comparison module;

[0022] The counting module includes at least one digital counter. The enable terminal of the digital counter receives the first control signal. The digital counter counts under the drive of a clock signal and outputs real-time counting results.

[0023] The comparison module includes at least one digital comparator. One end of the digital comparator receives the real-time counting result, and the other end receives a delay parameter preset by the interactive control module. When the real-time counting result exceeds the delay parameter, the digital comparator outputs the second control signal.

[0024] Preferably, the circuit selection module includes a selection module and an enable module;

[0025] The selection module includes a multiplexer logic circuit. The input terminal of the multiplexer logic circuit receives the second control signal, and the output terminal is connected to the gate of each MOSFET in the first switch control module. The multiplexer logic circuit selects to turn on a specific resistor path and turns off the other paths according to the logic state combination of the second control signal.

[0026] The enabling module includes a NOR gate logic circuit. The input terminal of the NOR gate logic circuit receives the second control signal, and the output terminal is connected to the circuit delay module and the second switch control module in the current judgment module. After receiving the second control signal, the NOR gate logic circuit outputs a low-level lockout signal to disable the counting function of the circuit delay module and cut off the input path of the voltage signal.

[0027] Preferably, the interactive control module includes a reset module and a mode selection module;

[0028] The reset module includes a reset button, which is connected to the clear terminal of the counting module. When the user presses the reset button, the reset module sends a reset signal to reset the state of the counting module and the circuit selection module.

[0029] The mode selection module includes a pin header array and a jumper cap. Function presets are achieved by changing the physical connection state of the jumper cap on the pin header array.

[0030] Preferably, the step of achieving functional preset by changing the physical connection state of the jumper cap on the pin array includes:

[0031] When setting the delay parameter: use jumper caps to short-circuit multiple reference data input pins of the comparison module to the high-level end or the low-level end respectively, and set the preset delay parameter in binary code form;

[0032] When controlling the conduction state of each resistor path in the current measurement module: the physical connection state between each alternative resistor path and the main measurement circuit in the current measurement module is controlled by inserting and removing jumper caps: when a jumper cap is inserted, the corresponding resistor path is connected to the main measurement circuit and is in a pending state, which is used to provide a specific current limiting resistance value after triggering; when a jumper cap is removed, the corresponding resistor path is physically disconnected from the main measurement circuit, which is used to achieve complete circuit cut-off protection after triggering.

[0033] Preferably, each MOSFET in the first switch control module has a pull-down resistor connected in parallel between its gate and source. When there is no drive signal, the pull-down resistor is used to pull down the gate potential of the MOSFET, thereby eliminating gate floating interference and accelerating the release of gate charge.

[0034] Preferably, the oscilloscope probe employs fiber optic isolation or radio frequency isolation technology.

[0035] This invention also provides a testing method for power electronic devices under extreme radiation conditions, based on the aforementioned testing system for power electronic devices under extreme radiation conditions, comprising the following steps:

[0036] Step S1: Connect the power electronic device under test, voltage source meter and signal generator to the test system, set the delay parameters and current limiting mode of the circuit delay module through the interactive control module, and set the voltage threshold.

[0037] Step S2: Start the irradiation source and voltage source meter, and collect the current flowing through the power electronic device under test in real time through the sampling resistor and convert it into a voltage signal;

[0038] Step S3: The voltage signal is monitored in real time using the current judgment module. When the voltage signal exceeds the voltage threshold, a first control signal is output to trigger the circuit delay module to start counting. If the first control signal continues to exist and the count value reaches the preset delay parameter, the circuit delay module outputs a second control signal.

[0039] Step S4: The circuit selection module controls the current measurement module to automatically switch the resistance path according to the second control signal, turn off the low resistance path and turn on the high resistance current limiting resistor path, so as to limit the current flowing through the power electronic device under test to a preset low level, while the enable module locks the circuit state.

[0040] Step S5: Record the transient current waveforms acquired by the current sampling module before and after the automatic current limiting switch using an oscilloscope probe, and analyze the breakdown process of the power electronic device;

[0041] Step S6: After the test is completed, reset the circuit state through the interactive control module to proceed with the next test.

[0042] The beneficial effects of the present invention include at least the following:

[0043] 1. The real-time current is converted into a voltage signal by the current measurement module and compared with the set voltage threshold by the current judgment module. This enables the rapid detection of abnormal current conditions. When the current exceeds the threshold, the system can output a control signal in a timely manner. The circuit selection module adjusts the current path and limits the current to a preset level, thereby effectively protecting power electronic devices from overcurrent damage and avoiding the problem of devices being directly damaged by a sudden increase in current in traditional methods.

[0044] 2. After detecting an abnormal current, the system will not take immediate action, but will wait for a preset delay time. The delay mechanism ensures that the testers have enough time to observe and record the device status during the transient breakdown process, avoiding missing key experimental data due to premature intervention. This helps to study the damage mechanism of power electronic devices under extreme irradiation conditions and solves the problem of difficulty in obtaining device information during transient breakdown in traditional methods.

[0045] 3. The current measurement module contains multiple parallel resistor paths. The circuit selection module can generate path selection instructions according to the control signal and flexibly control the conduction state of each resistor path, thereby realizing dynamic adjustment of the current path. This allows the system to adapt to the characteristics of different power electronic devices and accurately control the actual breakdown current level of different devices, solving the problem that the current limiting value of traditional voltage source meters is fixed and cannot adapt to the inconsistency of devices. Attached Figure Description

[0046] Figure 1This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the structure of each module in the system of this invention embodiment;

[0048] Figure 3 This is a circuit diagram of the current measurement module according to an embodiment of the present invention;

[0049] Figure 4 This is a circuit diagram of the current determination module according to an embodiment of the present invention;

[0050] Figure 5 This is a circuit diagram of the circuit delay module according to an embodiment of the present invention;

[0051] Figure 6 This is a circuit diagram of the circuit selection module according to an embodiment of the present invention;

[0052] Figure 7 This is a schematic diagram illustrating the generation time of key signals in the test system of this invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0054] like Figure 1 As shown, this embodiment of the invention provides a testing system for power electronic devices under extreme irradiation scenarios, including: a current measurement module, a current judgment module, a circuit delay module, a circuit selection module, and an interactive control module.

[0055] The working principle of this testing system is as follows: the current measurement module monitors the current flowing through the power device under test in real time. When a single-event effect occurs, causing a sudden increase in current, the current signal is converted into a voltage signal and transmitted to the current judgment module. The current judgment module compares this signal with preset multi-segment thresholds and outputs a first control signal. The circuit delay module performs digital counting delay on the control signal to filter out noise and provide a physical observation window. After the delay, the circuit selection module sends a command to the current measurement module to switch the resistance path based on the logical judgment result, and simultaneously sends a command to the current judgment module to cut off the detection input. The interactive control module provides a manual reset and parameter configuration interface.

[0056] like Figure 2As shown, the current measurement module includes a current sampling module, a switch control module, and a current limiting module. This module is connected in series in the main circuit of the power device and is responsible for acquiring the current and performing current limiting operations.

[0057] The current sampling module includes a sampling resistor and an oscilloscope probe. In order to achieve high-precision current measurement, sampling resistors R1 and R2 with a resistance of 50Ω are selected as shunts in this embodiment of the invention to achieve radio frequency impedance matching.

[0058] An oscilloscope probe is used to acquire the voltage difference across a sampling resistor and calculates the actual current flowing through the power electronic device under test based on Ohm's law. To accurately measure minute current changes under high voltage, this embodiment of the invention preferably employs a TICP (Transient In-line Compatibility) radio frequency isolated probe. The TICP probe uses fiber optic or radio frequency isolation technology to achieve complete current isolation between the probe tip and the oscilloscope. This eliminates ground loops and provides a common-mode voltage withstand capability of up to 1.8kV.

[0059] Through this design, the system can effectively isolate high-voltage interference, and its noise floor can be as low as 10⁻. 7 The magnitude is on the order of A, which allows for the detection of extremely subtle changes in leakage current.

[0060] The first switch control module includes multiple metal-oxide-semiconductor field-effect transistors (MOSFETs). Each MOSFET is connected in series in a corresponding resistor path to control the opening and closing of that path, thereby enabling the switching of different resistor paths. When a resistor path is off, the MOSFET withstands a high voltage, limiting the current flowing through the device. When the circuit is in a non-triggered state, path 1 is on by default. Once an overcurrent is detected, the first switch control module closes path 1 according to an instruction and selects another path to conduct or directly cuts off the circuit. Each MOSFET has a pull-down resistor connected in parallel between its gate and source to ensure that the MOSFET gate voltage is strongly pulled low during initialization or when the signal is floating, maintaining a reliable off state and preventing false turn-on due to gate floating, thus avoiding unexpected connection of the high-voltage circuit. Simultaneously, to ensure operational safety and protect the low-voltage logic circuit, digital isolators are installed on the gate drive path of the first switch control module and the signal output path of the current judgment module. These isolation components achieve electrical isolation between the high-voltage power circuit ground and the low-voltage control circuit ground, effectively blocking the propagation of high-voltage surges to the control system.

[0061] The current limiting module includes multiple current limiting resistors and potentiometers with different resistance values. Multiple current limiting levels can be designed by pre-setting them.

[0062] like Figure 3As shown, multiple branches are connected in parallel below R2. Each branch consists of a MOSFET and a current-limiting resistor connected in series. The current-limiting mode during the test can be selected through the interactive control module, limiting different levels of current for different devices. Alternatively, the circuit can be directly cut off when the current reaches a threshold, minimizing the current level flowing through the circuit and maximizing device protection. In the diagram, VH represents an external high voltage. The device under test (DUT) is connected in series with the current sampling module. R1 is the sampling resistor, and U1 and U2 are the voltages across the sampling resistor. Resistor R2 converts the current signal flowing through the DUT into a voltage signal U2, which is then transmitted to the current judgment module. VDD1 and VDD2 are the power supplies for the digital isolator, respectively. IN1, IN2, IN3, IN4 and OUT1, OUT2, OUT3, OUT4 are the input and output terminals of the digital isolator, respectively.

[0063] like Figure 4 As shown, the current judgment module includes a second switch control module, a voltage threshold setting module, a judgment module, and a circuit protection module. The core task of this module is to convert analog voltage signals into digital logic signals and classify the severity of breakdown. In the diagram, U3 is the non-inverting input voltage of the high-speed comparator, and a, b, and c are the inverting input voltages of the first, second, and third stage comparators, respectively, which are also the reference voltages of each comparator. VCC is the output voltage of the linear regulator, used to provide a stable power supply to the comparator chip.

[0064] The second switch control module includes a MOSFET connected in series in the input path of the voltage signal, used to control the opening and closing of the corresponding path. After the circuit triggers the current limiting protection action, the second switch control module receives a disable signal (low level) from the circuit selection module, quickly cutting off the path of the voltage signal to the high-speed comparator. This action effectively reduces the current leakage path after triggering current limiting and prevents the high-speed comparator from oscillating repeatedly due to subsequent current fluctuations.

[0065] The voltage threshold setting module includes a regulated power supply and a voltage divider resistor network, which are used to provide multiple voltage threshold gradients, set multiple current judgment intervals, and provide a stable reference voltage for the inverting input of the high-speed comparator.

[0066] The judgment module includes multiple high-speed comparators. The non-inverting input of each high-speed comparator receives a voltage signal from the current measurement module, while the inverting input receives a voltage threshold. When the voltage signal received at the non-inverting input is greater than the voltage threshold, the high-speed comparator outputs a high level; otherwise, it outputs a low level, thus generating a first control signal corresponding to different current ranges. Multiple high-speed comparators and voltage thresholds provide multiple threshold ranges, thereby classifying the magnitude of the voltage signal and consequently the current signal, and providing different control signals. The number of high-speed comparators and voltage thresholds can be further expanded according to the number of paths in the test system.

[0067] Because the voltage may fluctuate significantly during breakdown, a circuit protection module is connected in parallel to the input of the high-speed comparator. In this embodiment of the invention, a low-capacitance clamping diode is used. The clamping diode is connected to the input of the high-speed comparator to limit the voltage amplitude input to the high-speed comparator from exceeding the rated operating voltage of the high-speed comparator, thus preventing the input of the high-speed comparator from being broken down by high voltage.

[0068] like Figure 5 As shown, the circuit delay module includes a counting module and a comparison module. In the diagram, ENP and ENT are the two enable terminals of the counter, active high; CLR is the asynchronous clear terminal of the counter, active high; CLK is the clock signal input terminal of the counter, active on the rising edge; QD, QC, QB, and QA are the binary output terminals of the counter's counting result; A3, A2, A1, A0 and B3, B2, B1, B0 are the binary input terminals of the comparator. The input terminals of the circuit delay module are used to receive the first control signal and start the counting logic. When the duration of the first control signal reaches the preset delay parameter, a second control signal is output.

[0069] The counting module includes multiple digital counters. The enable terminal ENP of the digital counters receives a first control signal. The digital counters start counting only when the enable signal from ENP and the enable feedback ENT from the circuit selection module are both high and the clock signal arrives.

[0070] The comparison module includes multiple digital comparators. One end of the digital comparators, A3, A2, A1, and A0, receives the real-time counting results QD, QC, QB, and QA, while the other end, B3, B2, B1, and B0, receives the preset delay parameters from the interactive control module. When the real-time counting result exceeds the preset delay parameter, the OA>B pin outputs a second control signal, i.e., a high level; otherwise, it outputs a low level, thereby achieving the delay and transmission of the control signal.

[0071] The delay parameters B3, B2, B1, and B0 are preset via the pin headers of the interactive control module. This can increase the circuit delay to reduce the impact of signal spikes on circuit judgment and observe the damage caused by high breakdown current to components. Alternatively, it can decrease the circuit delay to allow the circuit selection module to act quickly, minimizing damage to components. The counting frequency of the digital counter is controlled by the externally input clock signal frequency. Assuming the preset delay parameter is 10 and the clock signal frequency is 100kHz, the delay time is... If the clock signal frequency is increased to 20MHz and the preset delay parameter is 1, the minimum delay can reach... This design can both filter out noise spikes and provide a microsecond-level observation window for observing the intermediate process of breakdown in power electronic devices.

[0072] like Figure 6 As shown, the circuit selection module includes a selection module and an enable module, which are used to receive the second control signal and perform logic decoding to generate a path selection instruction, control the conduction state of each resistor path in the current measurement module, adjust the current path flowing through the power electronic device under test, and limit the real-time current to a preset level.

[0073] In this embodiment of the invention, a priority logic decoding circuit is constructed using OR gates and NOT gates to implement the selector function. Since the signal output by the preceding current judgment module is a multi-bit parallel signal corresponding to different voltage thresholds, this decoding circuit is configured to select and activate a unique resistor path based on the position of the most significant bit in the input signal. This process is implemented using a combinational logic circuit composed of AND gates and NOT gates.

[0074] The multiple second control signals output by the circuit delay module are respectively input to the A0, A1, and A2 pins of the multiplexer and the A, B, and C pins of the OR gate. Based on the combination of multiple high-level signals from the circuit delay module, the multiplexer selects only one path at the output terminal to set it to high level, and sets the rest to low level, thereby controlling the first switch control module in the current measurement module to conduct the appropriate resistance path.

[0075] The enable module includes a NOR gate logic circuit. The input of the NOR gate logic circuit receives a second control signal, and its output is connected to the second switch control module in the circuit delay module and the current judgment module. After receiving the second control signal, the NOR gate logic circuit outputs a low-level lockout signal to disable the counting function of the circuit delay module and cut off the input path of the voltage signal. The input of the NOR gate logic circuit is connected to all delay control signals. If any delay control signal goes high, current limiting is triggered, and the Y-pin output of the NOR gate goes low. This low-level signal is fed back to the circuit delay module and the current judgment module, disabling the ENT pin of the digital counter to stop counting and turning off the MOSFET of the second switch control module.

[0076] The interactive control module includes a reset module and a mode selection module, which are used to set parameters during the test process and reset the state of the test system.

[0077] The mode selection module selects the access path combination in the current measurement module by shorting the header pins with a jumper cap. For example, it can select different current limiting values ​​for different devices, automatically switching to different resistance paths based on the breakdown current; alternatively, it can select a direct path cut-off mode. In this mode, after triggering the threshold, the selection module shuts off the initial path and does not conduct any backup current limiting paths, keeping the circuit in an open-circuit state, minimizing current and maximizing device protection. Simultaneously, the binary preset value of the comparator in the circuit delay module is set via the header pins.

[0078] The reset module includes a physical button connected to the clear pin of the counter. When the button is pressed, the reset signal goes high, and the reset signal output by the reset module is input to the CLR pin of the counter, causing the counter to be asynchronously cleared and the circuit state to be reset, ready for the next test.

[0079] Based on the above testing system, this invention proposes a testing method for power electronic devices under extreme radiation conditions. The timing sequence of key signals in the circuit during the testing process is as follows: Figure 7 As shown in the figure, C1, C2, and C3 are the control signals output from the first-stage comparator, second-stage comparator, and third-stage comparator, respectively, after being transmitted through the digital isolator; PC1, PC2, and PC3 are the delay control signals after the control signals C1, C2, and C3 are transmitted through the circuit delay module; E is the enable signal from the circuit selection module; P1, P2, P3, and P4 are the selection signals output from the priority logic decoding circuit after the delay control signals are transmitted; U1 and U2 are the voltages across the sampling resistor R1; I is the actual current value through the device under test; a, b, and c are the inverting input voltages of the first-stage comparator, second-stage comparator, and third-stage comparator, respectively, which are also the reference voltages of each comparator; I0 is the current flowing through the device under test corresponding to the reference voltage b of the second-stage comparator; I1 and I2 are the current values ​​reached by two different devices after a single-event breakdown; I1 ’ and I2 ’ The current limiting values ​​for two devices with breakdown currents of I1 and I2, respectively, are shown in different current limiting modes for different devices. ’ The current limiting values ​​for two devices with breakdown currents I1 and I2 under the same current limiting mode for different devices; t1 is the moment when the device experiences single-event breakdown, and t2 is the moment when the entire system completes the current limiting function. This represents the system delay from time point t1 to time point t2.

[0080] Specifically, the following steps are included:

[0081] S1: Connect the device under test, and set the voltage threshold, delay time, and current limiting mode through the interactive control module. The voltage thresholds are a, b, and c respectively, where a < b < c. For example, set a = 1.72V, b = 1.75V, and c = 1.78V.

[0082] S2: Start the experiment. Select the path signal P1 to be at a high level. The first switch control module in the current measurement module conducts path 1, representing the actual current passing through the device under test; at this time, the current is low, and the control signals C1, C2, C3, and the delay control signals PC1, PC2, PC3 are all at a low level, and the enable signal E is at a high level; the second switch control module is in a conducting state, allowing the voltage signal to enter the comparator.

[0083] S3: Breakdown detection stage (t1): Single - particle irradiation causes the device to break down, the current surges, and the voltage U2 steps up. Assume the current reaches A, causing the voltage U2 to be between the voltage thresholds b and c. At this time, the judgment module outputs C1 and C2 at a high level, and C3 at a low level. [[ID=k]]

[0084] S4: Delay counting stage (t1~t2): The high - level signals C1 and C2 start the counter. After a preset clock cycle, at time t2, the counter output is greater than the preset value, and the delay control signals PC1 and PC2 flip to a high level. During this delay period, the circuit keeps path 1 conducting, and the oscilloscope records the breakdown transient data.

[0085] S5: Current limiting and locking stage (t2): The selection module sets the output signal P1 to low according to the input, that is, turns off path 1, and sets P3 to high, that is, conducts path 3. The first switch control module in the current measurement module switches the current path to the high - resistance path 3, thereby limiting the current to a lower level. At the same time, the enable module detects that the PC signal becomes high and flips the enable signal E to a low level. This low - level signal immediately turns off the second switch control module in the current judgment module, cutting off the comparator input. At the same time, the counter is disabled, and the circuit enters a locked state and no longer responds to subsequent changes.

[0086] S6: Reset: After the test is completed, reset the circuit through the button of the interactive control module to prepare for the next experiment.

[0087] The testing method of this invention can prevent devices from burning out due to excessive power caused by a rapid increase in breakdown current during power device irradiation experiments. It can quickly reduce the current to a reasonable level after detecting that the current exceeds the threshold without additional manual intervention. Simultaneously, it allows observation of the specific breakdown current values ​​of different devices, facilitating the study of differences between devices and the intermediate process and mechanism of breakdown. Furthermore, it can continuously monitor the current changes of power devices before and after breakdown during irradiation experiments. The current limiting function has a minimum delay time of a few microseconds, which can be set independently, and the current accuracy can reach 10⁻⁶. -7 The voltage range is in the A-level range and can be tested up to 1700V.

[0088] By setting multiple threshold ranges and current limiting values, the test method of this invention can automatically select appropriate paths for different levels of breakdown current values ​​to perform different current limiting. It can be used to study the specific impact of different currents on the device after breakdown. The ranges and the number of components can be expanded by themselves, and only duplicate modules need to be added according to the circuit structure.

[0089] The testing system of this invention measures the electrical characteristics before and after irradiation testing to understand the degradation of the power device under irradiation conditions. The system is simple to operate, has a user-friendly interface, and can automatically complete the current limiting process without additional operation after setting the conditions and starting the test. After the test is completed, the circuit state can be quickly reset to facilitate the next test, thus improving testing efficiency.

[0090] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; only preferred embodiments of the present invention are illustrated. The descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. As long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0091] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A testing system for power electronic devices under extreme irradiation conditions, characterized in that, include: The module includes a current measurement module, a current judgment module, a circuit delay module, a circuit selection module, and an interactive control module. The current measurement module includes multiple parallel resistor paths for converting the real-time current flowing through the power electronic device under test into a voltage signal. The current judgment module compares the voltage signal with a set voltage threshold, and outputs a first control signal when the voltage signal exceeds the set voltage threshold. The circuit delay module receives the first control signal and starts counting. When the duration of the first control signal reaches a preset delay parameter, it outputs the second control signal. The circuit selection module receives the second control signal and performs logic decoding to generate a path selection instruction, which controls the conduction state of each resistor path in the current measurement module, adjusts the current flowing through the power electronic device under test, and limits the real-time current to a preset level. The circuit selection module includes a selection module and an enable module; The selection module includes a multiplexer logic circuit. The input terminal of the multiplexer logic circuit receives the second control signal, and the output terminal is connected to the switching device of each resistor path in the current measurement module. The multiplexer logic circuit selects to turn on a specific resistor path and turns off the other paths according to the logic state combination of the second control signal. The enabling module includes a NOR gate logic circuit. The input terminal of the NOR gate logic circuit receives the second control signal, and the output terminal is connected to the circuit delay module and the current judgment module. After receiving the second control signal, the NOR gate logic circuit outputs a low-level lock signal to disable the counting function of the circuit delay module and cut off the input path of the voltage signal. The interactive control module is used to set parameters during the test process and reset the state of the test system.

2. The testing system for power electronic devices under extreme irradiation conditions according to claim 1, characterized in that: The current measurement module includes a current sampling module, a first switch control module, and a current limiting module; The current sampling module includes a sampling resistor and an oscilloscope probe. The sampling resistor is connected in series in the main circuit of the power electronic device under test, and the oscilloscope probe is used to acquire the voltage difference across the sampling resistor. The first switch control module includes multiple metal-oxide-semiconductor field-effect transistors (MOSFETs), each MOSFET being connected in series in a corresponding resistor path; The current limiting module includes multiple current limiting resistors with different resistance values. The current limiting resistors are connected in series with the MOSFET to form multiple parallel resistor paths.

3. The testing system for power electronic devices under extreme irradiation conditions according to claim 2, characterized in that: The current judgment module includes a second switch control module, a voltage threshold setting module, a judgment module, and a circuit protection module; The second switch control module includes a metal-oxide-semiconductor field-effect transistor (MOSFET) for controlling the opening and closing of the corresponding path, and for withstanding a high voltage when the path is turned off, thereby limiting the current flowing through the power electronic device under test. The voltage threshold setting module includes a regulated power supply and a voltage divider resistor network, used to provide multiple voltage threshold gradients and set multiple current judgment intervals; The judgment module includes multiple high-speed comparators. The non-inverting input of the high-speed comparator receives a voltage signal from the current measurement module, and the inverting input receives the voltage threshold. When the voltage signal exceeds the set voltage threshold, the first control signal corresponding to different current ranges is output. The circuit protection module includes a clamping diode connected to the input terminal of the high-speed comparator, which is used to limit the voltage amplitude input to the high-speed comparator from exceeding the rated operating voltage of the high-speed comparator.

4. The testing system for power electronic devices under extreme irradiation conditions according to claim 3, characterized in that: The circuit delay module includes a counting module and a comparison module; The counting module includes at least one digital counter. The enable terminal of the digital counter receives the first control signal. The digital counter counts under the drive of a clock signal and outputs real-time counting results. The comparison module includes at least one digital comparator. One end of the digital comparator receives the real-time counting result, and the other end receives a delay parameter preset by the interactive control module. When the real-time counting result exceeds the delay parameter, the digital comparator outputs the second control signal.

5. A testing system for power electronic devices under extreme irradiation conditions according to claim 4, characterized in that: The interactive control module includes a reset module and a mode selection module; The reset module includes a reset button, which is connected to the clear terminal of the counting module. When the user presses the reset button, the reset module sends a reset signal to reset the state of the counting module and the circuit selection module. The mode selection module includes a pin header array and a jumper cap. Function presets are achieved by changing the physical connection state of the jumper cap on the pin header array.

6. A testing system for power electronic devices under extreme irradiation conditions according to claim 5, characterized in that: The method of achieving functional preset by changing the physical connection state of the jumper cap on the pin header array includes: When setting the delay parameter: use jumper caps to short-circuit multiple reference data input pins of the comparison module to the high-level end or the low-level end respectively, and set the preset delay parameter in binary code form; When controlling the conduction state of each resistor path in the current measurement module: the physical connection state between each alternative resistor path and the main measurement circuit in the current measurement module is controlled by inserting and removing jumper caps: when a jumper cap is inserted, the corresponding resistor path is connected to the main measurement circuit and is in a pending state, which is used to provide a specific current limiting resistance value after triggering; when a jumper cap is removed, the corresponding resistor path is physically disconnected from the main measurement circuit, which is used to achieve complete circuit cut-off protection after triggering.

7. A testing system for power electronic devices under extreme irradiation conditions according to claim 2, characterized in that: In the first switch control module, each MOSFET has a pull-down resistor connected in parallel between its gate and source. When there is no drive signal, the pull-down resistor is used to pull down the gate potential of the MOSFET, thereby eliminating gate floating interference and accelerating the release of gate charge.

8. A testing system for power electronic devices under extreme irradiation conditions according to claim 2, characterized in that: The oscilloscope probe uses fiber optic isolation or radio frequency isolation technology.

9. A testing method for power electronic devices under extreme irradiation conditions, implemented based on a testing system for power electronic devices under extreme irradiation conditions as described in any one of claims 1-8, characterized in that, Includes the following steps: Step S1: Connect the power electronic device under test, voltage source meter and signal generator to the test system, set the delay parameters and current limiting mode of the circuit delay module through the interactive control module, and set the voltage threshold. Step S2: Start the irradiation source and voltage source meter, and collect the current flowing through the power electronic device under test in real time through the sampling resistor and convert it into a voltage signal; Step S3: The voltage signal is monitored in real time using the current judgment module. When the voltage signal exceeds the voltage threshold, a first control signal is output to trigger the circuit delay module to start counting. If the first control signal continues to exist and the count value reaches the preset delay parameter, the circuit delay module outputs a second control signal. Step S4: The circuit selection module controls the current measurement module to automatically switch the resistance path according to the second control signal, turn off the low resistance path and turn on the high resistance current limiting resistor path, so as to limit the current flowing through the power electronic device under test to a preset low level, while the enable module locks the circuit state. Step S5: Record the transient current waveforms acquired by the current sampling module before and after the automatic current limiting switch using an oscilloscope probe, and analyze the breakdown process of the power electronic device; Step S6: After the test is completed, reset the circuit state through the interactive control module to proceed with the next test.

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