Test system and method for power electronic device in extreme irradiation scene

Abstract

The invention provides a test system and method for a power electronic device in an extreme irradiation scene, and the system comprises a current measurement module which comprises a plurality of resistor paths connected in parallel, and converts the real-time current flowing through the to-be-tested power electronic device into a voltage signal; the current judgment module is used for comparing the voltage signal with a set voltage threshold value and outputting a first control signal when the voltage signal exceeds the set voltage threshold value; the circuit delay module is used for receiving the first control signal, starting counting and outputting a second control signal when the duration of the first control signal reaches a preset delay parameter; the circuit selection module is used for receiving the second control signal, performing logic decoding, generating a path selection instruction, controlling the conduction state of each resistor path in the current measurement module, adjusting the magnitude of the current flowing through the power electronic device to be measured, and limiting the real-time current at a preset level; and the interaction control module is used for setting parameters in the test process and resetting the state of the test system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of circuit protection, and particularly relates to a test system and method for power electronic devices in an extreme irradiation scenario. BACKGROUND

[0002] Power electronic devices have high-voltage resistance and large-current carrying capacity, and have low conduction loss, high switching speed and strong surge resistance, and can realize efficient conversion and control of electric energy. As the core components in power electronics, radio frequency power amplification and harsh environment applications, the performance and reliability of power electronic devices directly determine the operation efficiency, volume cost and service life of terminal equipment. However, the application of power electronic devices in extreme environments such as aerospace, nuclear industry and the like faces the reliability problems of space irradiation damage and performance degradation, and the irradiation failure mechanism thereof needs to be further studied.

[0003] Traditional power device irradiation experiments are carried out under neutron sources, proton sources, heavy ion sources and voltage source tables and the like devices, and the experimental cost is high. When the power device is induced to generate a large number of carriers by single particle irradiation under high voltage stress, the breakdown of the device will occur, which is manifested as a sudden increase in the current passing through the device. On the one hand, the limited current value of the circuit needs to be set by the voltage source table; on the other hand, when the circuit current reaches the current limiting value of the voltage source table, the current will remain unchanged at this current value.

[0004] The traditional irradiation measurement method is easy to directly damage the power device in a short time, and cannot study the intermediate process and mechanism of irradiation damage of the power device. The power device may have a large inconsistency at present, and different devices have different breakdown current values, but are limited to a fixed value of the current limiting value of the voltage source table, so that the current limiting value of different devices is constrained to the same upper limit, so that the actual breakdown current level of different devices cannot be analyzed. When the circuit current reaches the current limiting value of the voltage source table, the current will remain unchanged at this current value, and cannot be automatically limited to a relatively low level, so that the device is damaged and burned, and it is difficult to analyze the irradiation damage mechanism. When the tester observes the breakdown of the device and then closes the voltage source table, a long time has passed, the device at the moment of transient breakdown cannot be obtained, the intermediate process cannot be studied, the experimental device is wasted, and the expected needs of the experiment cannot be met. SUMMARY

[0005] The application provides a test system and method for power electronic devices in an extreme irradiation scenario, which solves the problem that the traditional irradiation measurement method is easy to directly damage the power device in a short time and cannot study the intermediate process of irradiation damage of the power device.

[0006] To solve the above technical problems, the application provides a test system for power electronic devices in an extreme irradiation scene, 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 comprises a plurality of parallel resistance paths for converting 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 end of the circuit delay module 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.

[0010] The circuit selection module 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 under test, and limits the real-time current to a preset level.

[0011] The interactive control module is used for setting parameters in the test process and resetting the state of the test system.

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

[0013] The current sampling module comprises a sampling resistor and an oscilloscope probe, the sampling resistor is connected in series in the main loop of the power electronic device under test, and the oscilloscope probe is used for collecting the voltage difference across the sampling resistor.

[0014] The first switch control module comprises a plurality of metal oxide semiconductor field effect transistors (MOSFETs), and each MOSFET is connected in series in a corresponding resistance path.

[0015] The current limiting module comprises a plurality of current limiting resistors with different resistances, and the current limiting resistors are connected in series with the MOSFETs to form a plurality of parallel resistance paths.

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

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

[0018] The voltage threshold setting module comprises a voltage stabilizer and a voltage dividing resistor network, which are used to provide multiple gradient voltage thresholds to set multiple current judging intervals;

[0019] The judging module comprises multiple high-speed comparators, whose non-inverting input terminals receive the voltage signal from the current measuring module and whose inverting input terminals receive the voltage threshold, and when the voltage signal exceeds the set voltage threshold, the high-speed comparators output the first control signal corresponding to different current intervals;

[0020] The circuit protection module comprises a clamping diode, which is connected to the input terminal of the high-speed comparator, and is used to limit the voltage amplitude input to the high-speed comparator to not exceed the rated working voltage of the high-speed comparator.

[0021] Preferably, the circuit delay module comprises a counting module and a comparison module.

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

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

[0024] Preferably, the circuit selection module comprises a selection module and an enable module.

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

[0026] The enable module comprises an NAND gate logic circuit, whose input terminal receives the second control signal and whose output terminal is connected to the circuit delay module and the second switch control module in the current judging module, and after receiving the second control signal, the NAND gate logic circuit outputs a low-level locking 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 comprises a reset module and a mode selection module.

[0028] The reset module comprises a reset button connected to a clear end of the counting module, and when a 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 comprises a pin array and a jumper cap, and the function preset is achieved by changing the physical connection state of the jumper cap on the pin array.

[0030] Preferably, the function preset achieved by changing the physical connection state of the jumper cap on the pin array comprises:

[0031] When setting the delay parameter, the jumper cap is used to short the multiple reference data input pins of the comparison module to the high level end or the low level end respectively, so as to set the preset delay parameter in the form of binary coding.

[0032] When controlling the conduction state of each resistance path in the current measurement module, the jumper cap is used to control the physical communication state of each alternative resistance path in the current measurement module and the main measurement loop: when the jumper cap is inserted, the corresponding resistance path is connected to the main measurement loop and is in the standby state, and is used to provide a specific current limiting resistance value after triggering; when the jumper cap is removed, the corresponding resistance path is physically disconnected from the main measurement loop, and is used to realize complete circuit protection after triggering.

[0033] Preferably, the gate and the source of each MOSFET in the first switch control module are connected in parallel with a pull-down resistor, which is used to pull down the gate potential of the MOSFET when there is no driving signal, so as to eliminate gate floating interference and accelerate gate charge release.

[0034] Preferably, the oscilloscope probe adopts optical fiber isolation or radio frequency isolation technology.

[0035] The application also provides a test method for power electronic devices in an extreme irradiation scene, which is realized based on the above-mentioned test system for power electronic devices in an extreme irradiation scene and comprises the following steps:

[0036] Step S1: connecting the power electronic device to be tested, the voltage source table and the signal generator to the test system, setting the delay parameter and the current limiting mode of the circuit delay module through the interactive control module, and setting the voltage threshold value;

[0037] Step S2: starting the irradiation source and the voltage source table, and collecting the current flowing through the power electronic device to be tested in real time through the sampling resistor and converting it into a voltage signal;

[0038] Step S3: Real-time monitoring of the voltage signal by the current judgment module, when the voltage signal exceeds the voltage threshold, outputting a first control signal to trigger the circuit delay module to start counting, if the first control signal persists and the count value reaches a 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, turns off the low resistance path and turns on the high resistance current limiting resistance path, limits the current flowing through the power electronic device to be tested to a preset lower level, and the enable module locks the circuit state;

[0040] Step S5: Record the transient current waveform collected by the current sampling module before and after the automatic current limiting switch through the 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 for the next test.

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

[0043] 1. The current measurement module converts the real-time current into a voltage signal, and the current judgment module compares it with the set voltage threshold, which can quickly detect abnormal current conditions, and when the current exceeds the threshold, the system can output a control signal in time, adjust the current path through the circuit selection module, and limit the current to a preset level, thereby effectively protecting the power electronic device from overcurrent damage, avoiding the problem of direct damage of the device due to sudden increase of current in the traditional method;

[0044] 2. After detecting the abnormal current, the system does not take immediate measures, but waits for a preset delay time, and the setting of the delay mechanism can ensure that the test personnel have enough time to observe and record the device state during the transient breakdown process, avoid missing critical experimental data due to premature intervention, and help to deeply study the damage mechanism of power electronic devices under extreme radiation conditions, solving the problem of difficult to obtain device information during transient breakdown in the traditional method;

[0045] 3. The current measurement module includes multiple parallel resistance paths, and the circuit selection module can generate path selection instructions according to the control signal to flexibly control the conduction state of each resistance path, thereby realizing dynamic adjustment of the current path, so that the system can adapt to the characteristics of different power electronic devices, accurately control the actual breakdown current level of different devices, and solve the problem of fixed current limiting value of the traditional voltage source meter and inability to adapt to device inconsistency. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1A system structure schematic diagram of an embodiment of the present application;

[0047] Figure 2 A structure schematic diagram of each module in a system of an embodiment of the present application;

[0048] Figure 3 A circuit diagram of a current measurement module of an embodiment of the present application;

[0049] Figure 4 A circuit diagram of a current judgment module of an embodiment of the present application;

[0050] Figure 5 A circuit diagram of a circuit delay module of an embodiment of the present application;

[0051] Figure 6 A circuit diagram of a circuit selection module of an embodiment of the present application;

[0052] Figure 7 A generation time schematic diagram of key signals in a test system of an embodiment of the present application. DETAILED DESCRIPTION

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

[0054] As shown in Figure 1 , an embodiment of the present application provides a test system for power electronic devices in an extreme irradiation scenario, which comprises 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 the test system is as follows: the current measurement module is used to monitor the current flowing through the power device to be tested in real time, when a single particle effect occurs to cause a sudden increase in the current, the current signal is converted into a voltage signal and transmitted to the current judgment module; the current judgment module compares the signal with a plurality of preset threshold values 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 ends, the circuit selection module sends an instruction to the current measurement module to switch the resistance path according to the logical judgment result, and sends an instruction to the current judgment module to cut off the detection input; and the interactive control module is used to provide a manual reset and a parameter configuration interface.

[0056] As shown in Figure 2As shown, the current measurement module includes a current sampling module, a switch control module and a current limiting module, which are connected in series in the main circuit of the power device, responsible for current collection and current limiting operation.

[0057] The current sampling module includes sampling resistors and an oscilloscope probe, in order to achieve high-precision current measurement, the embodiments of the present application select sampling resistors R1 and R2 with a resistance of 50Ω as shunters to achieve radio frequency impedance matching.

[0058] The oscilloscope probe is used to collect the voltage difference across the sampling resistors, and the actual current value through the power electronic device under test is calculated according to Ohm's law. In order to accurately measure the weak current change under high voltage, the embodiments of the present application preferably use a TICP radio frequency isolation probe, which uses optical fiber or radio frequency isolation technology to achieve complete current isolation between the probe tip and the oscilloscope. Thus, the ground loop is eliminated, and a common-mode voltage tolerance of up to 1.8kV is provided.

[0059] Through this design, the system can effectively isolate high-voltage interference, and the noise floor can be as low as 10⁻ 7 A magnitude, so it can capture extremely weak leakage current changes.

[0060] The first switch control module includes a plurality of metal oxide semiconductor field effect transistors (MOSFETs), each MOSFET is connected in series in a corresponding resistance path, and is used to control the opening and closing of the corresponding resistance path, so as to realize the conduction and switching of different resistance paths, and to limit the current flowing through the device when the resistance path is turned off. When the circuit is in a non-trigger state, the default path 1 is turned on; once overcurrent is detected, the first switch control module closes path 1 according to the instruction and selects other paths to be turned on or directly cuts off the circuit. A pull-down resistor is connected in parallel between the gate and the source of each MOSFET, which ensures that the MOSFET gate voltage is pulled to a low level when initialized or the signal is suspended, and is in a reliable off state, preventing false conduction caused by floating gate, thereby avoiding turning on the high-voltage loop at unexpected times. At the same time, in order to ensure the safety of operation and protect the low-voltage logic circuit, a digital isolator is arranged on the gate drive path of the first switch control module and the signal output path of the current judgment module. These isolation elements realize the electrical isolation of the high-voltage power loop and the low-voltage control loop, effectively blocking the propagation of high-voltage surges to the control system.

[0061] The current limiting module includes a plurality of current limiting resistors with different resistances and a potentiometer, and multiple current limiting gears can be designed by pre-setting.

[0062] For example, Figure 3As shown, the lower part of R2 is connected in parallel with multiple branches, each of which is formed by a MOSFET and a current-limiting resistor in series. Through the interactive control module, the current-limiting mode during the test process can be selected to limit the current of different devices to different degrees. Alternatively, the current path can be directly cut off after the current reaches a threshold value to reduce the current level flowing through the circuit to the lowest level and maximize the protection of the device. In the figure, VH is an external high voltage, the device under test is connected in series with the current sampling module, R1 is a sampling resistor, U1 and U2 are the voltages across the sampling resistor, the resistor R2 converts the current signal flowing through the device under test into a voltage signal U2 and transmits it to the current judgment module, VDD1 and VDD2 are the power supply voltages across the digital isolator, IN1, IN2, IN3, IN4 and OUT1, OUT2, OUT3, OUT4 are the input and output terminals of the digital isolator, respectively.

[0063] As shown in Figure 4 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 the analog voltage signal into a digital logic signal and classify the severity of breakdown. In the figure, U3 is the non-inverting input voltage of the high-speed comparator, a, b, and c are the inverting input voltages of the first, second, and third comparators, respectively, that is, the reference voltages of the comparators. VCC is the output voltage of the linear voltage regulator, which is used to provide a stable power supply for the comparator chip.

[0064] The second switch control module includes a metal oxide semiconductor field effect transistor (MOSFET) connected in series on the input path of the voltage signal, which is 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 from the circuit selection module, which is a low level, quickly cutting off the path of the voltage signal to the high-speed comparator. This action can effectively reduce the current leakage path after triggering the current-limiting and prevent the high-speed comparator from repeatedly oscillating due to subsequent current fluctuations.

[0065] The voltage threshold setting module includes a voltage regulator and a voltage dividing resistor network, which is used to provide multiple gradient voltage thresholds, set multiple current judgment intervals, and provide stable reference voltages for the inverting input terminals 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 of the input B3, B2, B1, B0 are set in advance through the pin arrangement of the interaction control module, which can increase the circuit delay to reduce the influence of signal peaks on the circuit judgment, observe the damage of high breakdown current to the device, and also can reduce the circuit delay to make the circuit selection module act quickly and reduce the damage to the device. The counting frequency of the digital counter is controlled by the frequency of the external input clock signal, assuming that the preset delay parameter is 10 and the clock signal frequency is 100 kHz, then the delay time is ; if the clock signal frequency is increased to 20 MHz and the preset delay parameter is 1, the minimum delay can reach . This design can filter out noise peaks and provide a microsecond-level observation window for observing the intermediate process of power electronic device breakdown.

[0072] As shown in Figure 6 , the circuit selection module includes a selection module and an enable module, which is used for receiving the second control signal and performing logic decoding, generating a pass selection instruction, controlling the conduction state of each resistance path in the current measurement module, and adjusting the current path through the power electronic device to be measured to limit the real-time current at a preset level.

[0073] In the embodiment of the application, an AND gate and a NOT gate are used to build a priority logic decoding circuit to realize the selector function. Since the signals output by the front-stage current judgment module are multi-bit parallel signals corresponding to different voltage thresholds, the decoding circuit is configured to select only one resistance path to be turned on according to the position of the most significant bit in the input signal. This process is realized by a combination logic circuit composed of AND gates and NOT gates.

[0074] The multiple second control signals output by the circuit delay module enter the A0, A1 and A2 pins of the multiplexer and the A, B and C pins of the NOT gate, respectively. The multiplexer selects only one path to be high level and the others to be low level in the output end according to the combination of the multiple high level signals from the circuit delay module, so as to control the first switch control module in the current measurement module to turn on the appropriate resistance path.

[0075] The enable module includes a NOT gate logic circuit, the input end of the NOT gate logic circuit receives the second control signal, and the output end is connected with the circuit delay module and the second switch control module in the current judgment module. After receiving the second control signal, the NOT gate logic circuit outputs a low level locking signal to disable the counting function of the circuit delay module and cut off the input path of the voltage signal. The input end of the NOT gate logic circuit is connected with all the delay control signals. As long as any one of the delay control signals becomes high level, the Y pin of the NOT gate outputs low level, and the low level signal is fed back to the circuit delay module and the current judgment module, respectively, to disable the ENT pin of the digital counter and stop counting, and to turn 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 in 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 short-circuiting the jumper cap and the pin. For example, different device and different current limiting value modes can be selected, in which case the circuit is automatically switched to different resistance paths according to the breakdown current size; or a direct cut-off path mode can be selected, in which case the selection module will shut down the initial path and not turn on any standby current limiting path after the trigger threshold is reached, so that the circuit is in an open circuit state, the current is reduced to the minimum, and the device is maximally protected. The binary preset value of the comparator in the circuit delay module is set through the pin.

[0078] The reset module includes a physical button connected to the clear end of the counter. When the button is pressed, the reset signal is high, and the reset signal output by the reset module is input to the CLR pin of the counter, so that the counter is asynchronously cleared, the circuit state is reset, and the next test is prepared.

[0079] Based on the above test system, the embodiment of the present application proposes a test method for power electronic devices in an extreme irradiation scene. The key signal timing of the circuit in the test process is as shown in Figure 7 The C1, C2 and C3 in the figure are control signals output by the first, second and third comparators respectively after being transmitted through the digital isolator; PC1, PC2 and PC3 are delay control signals of the control signals C1, C2 and C3 after being transmitted through the circuit delay module; E is an enable signal from the circuit selection module; P1, P2, P3 and P4 are selection signals output by the delay control signals after being decoded by the priority logic decoding circuit; U1 and U2 are voltages across the sampling resistor R1; I is the actual current value through the device under test; a, b and c are the inverse input voltages of the first, second and third comparators, i.e., the reference voltages of the comparators; I0 is the current size through the device under test corresponding to the reference voltage b of the second comparator; I1 and I2 are the current sizes reached by two different devices after single event burnout; I1 ’ and I2 ’ correspond to the current limiting values of the two devices with the breakdown currents I1 and I2 in different device and different current limiting value modes, respectively; I ’ correspond to the current limiting values of the two devices with the breakdown currents I1 and I2 in different device and same current limiting value modes; t1 is the time when the device has single event burnout, t2 is the time when the system completes the current limiting function, and t2 is the delay of the system from the time point t1 to the time point t2.

[0080] Specifically includes the following steps:

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

[0082] S2: Start the experiment, select the pass signal P1 as high level, the first switch control module in the current measurement module is turned on pass 1, , which represents the actual current through the device under test; At this time, the current is low, the control signals C1, C2 and C3 and the delay control signals PC1, PC2 and PC3 are all low, and the enable signal E is high; The second switch control module is in the on state, allowing the voltage signal to enter the comparator.

[0083] S3: Breakdown detection phase (t1): Single particle irradiation causes device breakdown, current increases sharply, and voltage U2 jumps up. Assuming the current reaches A, resulting in a voltage U2 between voltage thresholds b and c, at which time the judgment module outputs C1 and C2 as high and C3 as low.

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

[0085] S5: Current limiting and locking phase (t2): The selection module sets the output signal P1 low, i.e. turns off pass 1, and sets P3 high, i.e. turns on pass 3, according to the input. The first switch control module in the current measurement module switches the current path to pass 3 with high resistance, thereby limiting the current to a low level. At the same time, the enable module detects that the PC signal is high, and flips the enable signal E to 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 the 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, and prepare for the next experiment.

[0087] The test method of the embodiment of the present application can prevent the device from burning out due to excessive power caused by rapid rise of breakdown current during the irradiation experiment of the power device, can rapidly reduce the current to a reasonable level after detecting that the current exceeds the threshold value without additional manual operation, and can also observe the specific breakdown current value of different devices to facilitate the research on the differences between devices and the intermediate process and mechanism of breakdown; meanwhile, the current change of the power device before and after breakdown in the irradiation experiment can be continuously observed, the minimum delay time of the current limiting function can reach several microseconds, the delay time can be autonomously set, and the current accuracy can reach 10 -7 A order of magnitude, and the test voltage range can be as high as 1700V.

[0088] By setting multiple threshold intervals and current limiting values, the test method of the embodiment of the present application can automatically select appropriate paths for different levels of breakdown current values to perform different current limiting, can be used to study the specific effects of different sizes of currents on the device after breakdown, and the number of intervals and elements can be expanded as needed by adding repeated modules according to the circuit structure.

[0089] The test system of the embodiment of the present application measures the electrical characteristics before and after the irradiation test, so as to understand the degradation of the power device under this irradiation condition; the system is simple to operate, the man-machine interaction is friendly, the preset conditions and the start of the test can automatically complete the current limiting process without additional operation, and the circuit state can be quickly reset after the test to facilitate the next test, thereby improving the test efficiency.

[0090] The technical features of the above embodiments can be combined arbitrarily, in order to make the description simple, not all possible combinations of the technical features in the above embodiments are described, only the preferred embodiments of the present application are expressed, and the description is more specific and detailed, but it should not be understood as limiting the scope of the present application. As long as the combination of these technical features does not exist contradictory, it should be considered as the scope of the present application.

[0091] It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the present application should be subject to 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 interactive control module is used to set parameters during the testing process and reset the state of the testing 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. A 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 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 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. 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.

6. 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.

7. A testing system for power electronic devices under extreme irradiation conditions according to claim 6, 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.

8. 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.

9. 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.

10. 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 1-9, 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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