Circuit safety insulation test method for intelligent power module

Abstract

The invention relates to the technical field of circuit testing, in particular to a circuit safety insulation testing method for an intelligent power module. The method comprises the following steps: establishing an electrical connection relationship between a golden finger in a test socket and an intelligent power module, and setting a test connection environment to obtain a test socket connection network; connecting a voltage detection end in the test socket connection network with a predetermined voltage, detecting the pin contact condition of each intelligent power module, and setting a voltage signal disconnection moment according to the pin contact condition; when the voltage signal disconnection moment arrives, the relay is controlled to disconnect the preset voltage, and meanwhile relay control connection between all the current injection ends in the test seat and the single-chip microcomputer is disconnected; the voltage detection end is switched to be connected to the high-voltage output end of the insulation and voltage resistance tester, and insulation performance detection is executed; and sorting defective products according to the insulation performance detection result, and displaying the current insulation performance detection result and the defective product sorting result. According to the invention, the safety and accuracy of the insulation test can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit testing, in particular to a circuit safety insulation test method of an intelligent power module. BACKGROUND

[0002] As the core component of power electronic systems, the packaging reliability of IPM (Intelligent Power Module) directly affects the service life and safety of the equipment. The current industry standard requires that the IPM module needs to pass the insulation withstand voltage test before leaving the factory, in order to verify that the plastic packaging process is defect-free. However, during the test, the slight deformation of the pin after the pin cutting and forming may cause poor contact between some pins and the test fixture, and the pins that are not short-circuited are easy to be high-voltage breakdown in high-voltage test, causing good product batch damage accidents.

[0003] Before the current insulation withstand voltage test, it is not detected whether the module pins are in good contact with the fingers of the test fixture, and high voltage is directly applied between the pins of the IPM module and the back heat sink. However, for IPM modules, which are multi-row and multi-pin devices, if a pin is deformed and does not contact the test finger, high voltage may be applied to the chip. Generally, the insulation withstand voltage is greater than 1500V, and the chip withstand voltage is generally only 600V or 1200V. Without good contact, the chip is very easy to break down, causing batch accidents. SUMMARY

[0004] Therefore, it is necessary to provide a circuit safety insulation test method of an intelligent power module to solve at least one of the above technical problems.

[0005] To achieve the above purpose, a circuit safety insulation test method of an intelligent power module is applied to a test seat, the test seat includes a display screen, a sorting machine, a current injection end, a controller, a single-chip microcomputer, an insulation withstand voltage tester, a relay electrically connected with the controller, and a gold finger integrated with a voltage detection end, wherein the sorting machine, the display screen, the gold finger, the current injection end, the single-chip microcomputer, and the insulation withstand voltage tester are electrically connected with the controller. The method comprises the following steps: Step S1: Establishing an electrical connection relationship between the gold finger in the test seat and the intelligent power module, and setting a test connection environment for the test seat with established electrical connection, to obtain a test seat connection network; Step S2: Connecting the voltage detection end in the test seat connection network to a predetermined voltage, detecting the pin contact condition of each intelligent power module, and setting the voltage signal disconnection time according to the pin contact condition; Step S3: when the voltage signal disconnection time arrives, control the relay to disconnect the predetermined voltage, and disconnect the relay control connection between all current injection ends in the test seat and the single-chip microcomputer; switch the voltage detection end to the high-voltage output end of the insulation withstand voltage tester, start the high-voltage loading path, and perform insulation performance detection; Step S4: according to the insulation performance detection result, sort out the defective products, and display the current insulation performance detection result and the sorting result of defective products on the display screen.

[0006] The application detects the contact state of the module pin by 5V voltage, evaluates the connection quality in real time, avoids high voltage directly loaded on the pin with poor contact to cause chip breakdown, sets an adjustable voltage signal disconnection period before high voltage loading, dynamically adjusts the disconnection time in combination with the voltage output state, introduces an intermittent low-duty cycle loading strategy, realizes the transitional voltage unloading and protection of the pin, finally switches to the insulation withstand voltage test process, and combines the environmental parameters and material information to correct the preliminary detection result, automatically completes the physical sorting of qualified products and defective products in combination with the sorter. Effectively solve the problem of batch good product damage caused by poor pin contact in the prior art, greatly improve the safety, accuracy and automation level of insulation test. BRIEF DESCRIPTION OF DRAWINGS

[0007] Other features, objects and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the accompanying drawings: Fig. 1 The step flowchart of the circuit safety insulation test method of the intelligent power module of the application; Fig. 2 The circuit structure schematic diagram of the test seat in the embodiment of the application; The implementation of the object of the application, functional characteristics and advantages will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0008] The technical method of the application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0009] Furthermore, the accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings:

[0010] It is to be understood that, although terms such as "first", "second", and so on can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of the exemplary embodiments, a first element can be referred to as a second element, and similarly a second element can be referred to as a first element. The term "and / or" as used herein includes any and all combinations of one or more of the associated associated items.

[0011] To achieve the above object, there is provided Figs. 1-2 The present application provides a circuit safety insulation test method for an intelligent power module, comprising the following steps: Step S1: Establishing an electrical connection relationship between a gold finger in a test seat and an intelligent power module, setting a test connection environment for the test seat with the established electrical connection, and obtaining a test seat connection network; In this embodiment, a test seat with a gold finger structure is arranged on a test bench. The gold finger adopts a double-spring piece clamping structure, and is in stable physical contact with each pin of the intelligent power module through a press-fitting method. Each pin is composed of a pair of metal contact pieces to form a Kelvin connection for realizing independent paths of voltage detection and current injection. All voltage detection paths (Sense end) in the test seat are connected to a unified node, and are selectively connected to a 5V low-voltage source or a high-voltage positive end of an insulation voltage tester through a relay, forming a switchable test input network. At the same time, all current injection paths (Force end) are one-to-one connected to a relay and then connected to a control unit single-chip microcomputer, forming a current control network. Finally, the voltage detection network and the current injection control network are integrated to build a test seat connection network, and the on-off state of the relay, the input path configuration state, and the electrical parameter state of each node are initialized and collected by the main control single-chip microcomputer, to ensure that the test environment configuration is correct.

[0012] Step S2: Connecting the voltage detection end in the test seat connection network to a predetermined voltage, detecting the pin contact condition of each intelligent power module, and setting the voltage signal disconnection time according to the pin contact condition; In this embodiment, the main control single-chip microcomputer controls the relay to be turned on, so that the voltage detection end is connected to the 5V voltage source, and the current injection end is loaded with 5V DC voltage in sequence. The electrical response of each pin is judged by returning data through the voltage detection end. Within 10ms after the completion of loading in each injection channel, 3 groups of voltage data are sampled. If the stable level value of the sampled data is between 4.9V and 5.1V, the voltage build-up time is not more than 20ms, and the voltage fluctuation range is less than ±0.1V, it is determined that the pin contact is good. If any index does not meet the preset threshold, it is marked as poor contact, and the 5V voltage source connection is immediately disconnected to prevent further testing. After the completion of this stage of detection, the main control sets the voltage signal disconnection time period from the current time to the transition stage before the planned high voltage loading, and sets the initial disconnection time as the current time plus 500ms. During this period, the voltage output state of the Sense end is collected in real time. If the output level fluctuation amplitude exceeds 0.1V in three consecutive periods, the disconnection time is delayed by 50-100ms with the average fluctuation amplitude as the weight; if the output is continuously stable, the original disconnection time is maintained. Finally, the disconnection time point is determined according to real-time feedback, and 50ms before disconnection, the relay is controlled to reduce the voltage injection duty cycle to less than 50% in an intermittent loading mode to buffer the electrical pressure.

[0013] Step S3: when the voltage signal disconnection time arrives, control the relay to disconnect the predetermined voltage, and simultaneously disconnect the relay control connection between all current injection ends in the test socket and the single-chip microcomputer; switch the voltage detection end to be connected to the high-voltage output end of the insulation withstand voltage tester, and start the high-voltage loading path to perform insulation performance detection; In this embodiment, if the voltage signal disconnection time arrives, the main control single-chip microcomputer immediately controls the relay to disconnect the 5V voltage source, and simultaneously completely disconnects the connection path between all current injection ends and the single-chip microcomputer, to avoid the risk of high-voltage backflow. Then the relay is controlled to switch, so that all voltage detection ends are connected to the high-voltage output positive electrode of the insulation withstand voltage tester, to build a high-voltage loading path. At this time, the insulation withstand voltage tester starts to perform a preset program, loads a DC voltage of 1500V to each pin for a duration of 500ms, and simultaneously collects the leakage current value and compares it with the set tolerance threshold (such as 100μA). If the leakage current value of any pin exceeds the threshold, it is marked as poor insulation. In this stage, all channel leakage current data returned by the tester are stored and analyzed by the main control single-chip microcomputer, and the results are marked as preliminary insulation detection conclusions. At the same time, according to the test environment parameters collected by the on-site temperature and humidity sensor, combined with the material characteristics of the intelligent power module (such as the epoxy resin packaging voltage grade), it is automatically determined whether there is an environment-induced misjudgment. If it is confirmed that the abnormality is caused by environmental fluctuations, the related results are corrected.

[0014] Step S4: sorting out defective products according to the insulation performance detection result, and displaying the current insulation performance detection result and the sorting result of defective products on the display screen.

[0015] In another embodiment, if the insulation performance detection result has been completed and marked as qualified / defective, the product screening and result publishing stage is entered. In this embodiment, the master single-chip microcomputer generates a sorting control instruction according to the detection state of each module, and the instruction content includes the module number, the detection result, and the recommended physical sorting position number. The instruction is sent to the automatic sorting machine matched with the test platform, and after receiving the instruction, the sorting machine controls the mechanical arm to move the module to be tested from the test station to the corresponding collection area (for example, the qualified product area A and the defective product area B). At the same time, the display screen updates the current detection state in real time, including the number of modules that have completed detection, the insulation detection data chart of the current module, the final sorting position, and the sorting statistical summary, which facilitates the operator to check and record. In addition, in order to meet the production traceability requirement, the system also exports all the detection and sorting information as a CSV format file and stores it in the test master platform, forming a complete data archiving chain.

[0016] Fig. 2 The circuit structure schematic diagram of the test seat in the embodiment of the application is shown in FIG. 1. Fig. 2 As shown in the figure, the test structure is built around the intelligent power module (DIP25), and presents an integrated circuit architecture of low-voltage detection-high-voltage loading-sorting control.

[0017] The central part of the figure is the pin arrangement structure of the intelligent power module, and the left and right sides are connected with the single-chip microcomputer through relays to realize the on-off control of each current injection end. The green connection part is the voltage signal detection path, which is connected to the voltage detection end and the insulation withstand voltage tester. The red path is the high-voltage loading channel, which is used to switch through the relay before testing to realize the path conversion of the 5V low-voltage signal and the HV high-voltage signal.

[0018] In the figure, 5V and HV+ respectively correspond to the output of the low-voltage power supply and the insulation withstand voltage tester, and the relay is used as a switching component to control the loading path of different power supplies. The single-chip microcomputer is connected with the display screen and the sorting machine module at the same time, which is convenient for real-time monitoring of the test state and control of product sorting. When testing the pins, the contact condition is judged through the voltage detection feedback signal to ensure that the contact screening is completed before high-voltage loading, and the risk of breakdown is avoided.

[0019] In addition, the relays in the figure are arranged in a symmetrical structure, with the input control end on the left and the output drive and feedback end on the right, realizing independent detection and control of the pin level. The overall structure is clear and logical, and fully guarantees the safety and controllability of the test.

[0020] Optionally, the test connection environment set in step S1 includes: The voltage detection terminals of the gold fingers of the test socket connected with the established electrical connection are connected to obtain a unified signal bus path, and the power positive terminal of the 5V voltage source and the insulation voltage tester is connected through the relay switching to obtain a voltage detection terminal connection network. In the embodiment, if the test system completes the intelligent power module insertion operation and detects that the test socket gold fingers establish initial physical contact with the module pins, the initialization configuration process of the test connection environment is started. All the gold fingers in the test socket are designed as Kelvin double contact structures, and two groups of Sense and Force end wires are drawn out. All the Sense end lines are connected to the unified main bus through the PCB inner layer to form a centralized voltage detection network. On this basis, a double-pole double-throw relay with a DPDT switching structure is configured to establish a switchable connection between the voltage detection main bus and two power source terminals: one is a 5V low-voltage source for contact detection, and the other is the high-voltage positive terminal of the insulation voltage tester for subsequent insulation performance detection. The digital control logic of the relay realizes the undisturbed switching between the two power sources, thereby constructing a complete and orderly voltage detection terminal connection network.

[0021] The current injection terminals of the test socket connected with the established electrical connection are connected to a relay, and the other end of the relay is connected to a single-chip microcomputer to obtain a current injection terminal connection network. In the embodiment, the Force end signal lines (i.e. injection terminals) in the test socket are connected to independent single-channel relay input terminals, and the output terminals of the relays are uniformly connected to the digital output pins of the control single-chip microcomputer. This structure realizes the separate control of the Force injection voltage for each pin, i.e. the single-chip microcomputer can independently drive each relay channel during the test process, thereby sequentially loading 5V voltage signals to each pin of the intelligent power module for bit-by-bit detection. At the same time, voltage holding time setting capacitors and surge absorbing elements are introduced into the relay control loop to ensure signal stability and no interference during switching. Through this structure, a current injection terminal connection network with timing control ability and fault channel isolation ability is constructed.

[0022] The voltage detection terminal connection network and the current injection terminal connection network are integrated to obtain a test socket connection network.

[0023] In this embodiment, the master single-chip microcomputer synchronously activates the control logic interfaces of the two types of networks, and reads all relay drive states, feedback signal states, and system internal contact state sensor data. After verifying that the connection integrity of each channel and the physical on-off relationship meet the test logic requirements, the system completes the synchronous integration of the two sub-networks, and establishes a four-in-one test connection structure network including the input path (Force), monitoring path (Sense), control path (single-chip microcomputer IO), and switching path (relay group). The network has the characteristics of low-voltage contact judgment, high-voltage loading switching, channel control, and real-time synchronization of state, and lays a physical layer foundation for subsequent voltage loading control and insulation judgment processes.

[0024] Optionally, the switching selection connection of the 5V voltage source and the power supply positive end of the insulation withstand voltage tester includes: When detecting the pin contact condition of each intelligent power module, the relay is controlled to be turned on, the voltage detection end connection network is connected to the 5V voltage source, and a low-voltage signal path is formed; When all pin contact condition detection is completed and it is confirmed that there is no abnormal contact, the voltage signal disconnection time is set, the relay is controlled to disconnect the 5V voltage source connection at the voltage signal disconnection time, and the voltage detection end connection network is switched and connected to the power supply positive end of the insulation withstand voltage tester, thereby constructing a high-voltage loading path.

[0025] In this embodiment, the master single-chip microcomputer activates the relay channels of each current injection end in turn, and applies 5V direct current voltage to all Force ends in the test seat one by one. In this stage, the voltage detection end network is switched to the 5V voltage source output by the central relay, forming a complete Kelvin low-voltage detection path. By monitoring the voltage feedback value of the Sense end, the voltage response fluctuation, rise time, and return voltage tolerance value of each pin are collected, and it is judged whether the pin is in good contact with the gold finger. If the feedback state of all pins meets the contact judgment conditions that the fluctuation amplitude is less than ±0.1V, the voltage rise time is less than 20ms, and the return voltage is between 4.9V and 5.1V, it is determined that the intelligent power module is in good contact, and enters the subsequent high-voltage preparation stage. At this time, the master single-chip microcomputer records the current time as the contact detection completion time point, and sets the voltage signal disconnection time period according to the preset logic, and sets the voltage signal disconnection time at the end of the time period.

[0026] In another embodiment, the pre-switching signal is sent 50 ms before the voltage signal disconnection time, and the following operations are performed: 1) drive all current injection terminals to pre-disconnect the relays between the single-chip microcomputer, cut off the control path to ensure that the relay channel is in a high resistance state; 2) control the relays to disconnect the connection between the voltage detection terminal and the 5V low-voltage source, completely disconnecting the low-voltage signal path. Subsequently, the control logic immediately switches the relay to the high-voltage loading state, connecting the voltage detection terminal network to the positive output terminal of the power supply of the insulation withstand voltage tester. After completing the high-voltage source switching, the high-voltage loading preparation instruction is executed, and the insulation test voltage of 1500V to 2500V is output by the withstand voltage tester to formally build the high-voltage loading path.

[0027] Optionally, the step S2 includes detecting the pin contact condition of each intelligent power module, and the detecting includes: According to the voltage detection terminal feedback after the 5V voltage signal is loaded on each current injection terminal in turn, the contact condition between all the gold fingers in the test seat and the pins of the intelligent power module is determined to be good or poor, wherein the determination of the contact condition includes: If the response voltage fluctuation amplitude in the voltage detection terminal feedback within a unit time does not exceed the fluctuation amplitude threshold ±0.1V, the voltage establishment time does not exceed the establishment time threshold 20ms, and the voltage return value of each pin is within the tolerance threshold of 4.9V to 5.1V, it is determined that the pin contact of the intelligent power module is good; If any one of the response voltage fluctuation amplitude, the voltage establishment time and the voltage return value of the voltage detection terminal feedback within a unit time exceeds the corresponding threshold, it is determined that the pin contact of the intelligent power module is poor, and the relay is immediately controlled to disconnect the 5V voltage source connection.

[0028] In this embodiment, the single-chip microcomputer of the test platform triggers the current injection terminals (Force terminals) connected to the pins of each intelligent power module in a fixed time sequence, so that the 5V voltage signal is loaded within a specified time window, and the feedback voltage signal of the corresponding voltage detection terminal (Sense terminal) is synchronously collected during the loading process. During each loading process, the frequency of the Sense terminal for collecting voltage is set to 1kHz, the duration of collecting voltage for each pin is not less than 100ms, and the corresponding feedback data is cached into the data collection module. The maximum voltage value, the minimum voltage value, the first response delay time and the average stable voltage value of each pin within the time period are collected.

[0029] In another embodiment, the control system performs contact state judgment according to the following judgment logic: 1) if the difference between the maximum voltage value and the minimum voltage value in the current pin collected data is less than ±0.1V, the first response delay time is less than 20ms, and the stable voltage value is between 4.9V and 5.1V, it is determined that the pin is in good contact; 2) if any of the detection results exceeds the above judgment threshold, the system will record the pin number corresponding to the contact as abnormal, and trigger a fault response signal at the same time.

[0030] Notably, when at least one pin is determined to be in poor contact, the central relay will be immediately controlled to disconnect the output connection of the 5V voltage source, preventing continuous pressure from causing local ablation or breakdown risk of the virtual pin due to abnormal sensing loop; at the same time, the module is marked as unqualified for re-inspection state, and subsequent entry into the insulation test process is prevented. If all pins complete detection under the above threshold conditions and the contact state is confirmed to be good, the current module can enter the high-voltage preparation process, entering the voltage disconnection timing phase. This ensures that the physical connection quality before high-voltage loading is controllable, avoiding the risk of high-voltage breakdown of the chip core structure due to unconnected pins, and improving the safety and accuracy of insulation testing.

[0031] Optionally, the voltage signal disconnection time in step S2 includes: The preset transition period from the time when the contact of the current detection pin is completed to the time before high-voltage loading is determined as the voltage signal disconnection time period, and the specific time when the voltage signal disconnection time period ends is determined as the initial voltage signal disconnection time; During the voltage signal disconnection time period, the control system controls each current injection end to maintain a 5V voltage input, real-time samples the voltage output state, and adjusts the initial voltage signal disconnection time according to the voltage output state to obtain the voltage signal disconnection time; When the voltage signal disconnection time period reaches 50ms before the voltage signal disconnection time, the control system controls each relay to pre-disconnect the connection between each current injection end of the test seat and the single-chip microcomputer, and simultaneously stops the input state of the voltage detection end.

[0032] In this embodiment, if all the pins of the intelligent power module are detected, the current time is immediately recorded as the pin contact detection completion time. Based on this time, a transition time period (e.g. 100ms to 200ms) is set in advance in combination with the high-voltage loading start time, which covers all preparation action times from detection completion to high-voltage loading. The single-chip microcomputer built-in timer starts timing, and the end time of the transition time period is marked as the initial voltage signal disconnection time. This disconnection time is used as a reference time point for subsequent control circuit switching and relay disconnection, to ensure a safe transition from low-voltage detection to high-voltage testing.

[0033] In some embodiments, the 5V voltage input of each current injection end is continuously maintained stable during the set voltage signal disconnection period (e.g. in the range of 100ms to 200ms), ensuring that the smart power module is in a low-voltage excitation state. At the same time, the single-chip microcomputer synchronously collects the voltage output state of each voltage detection end at a fixed sampling period (e.g. every 10ms), monitoring the voltage fluctuation amplitude and level stability. If the difference between the maximum and minimum values of the collected output voltage in three consecutive sampling periods exceeds 0.1V, it is determined that the voltage state is abnormal. According to the abnormal amplitude, the single-chip microcomputer dynamically adjusts the initial voltage signal disconnection time, delaying the disconnection time to ensure system voltage stability and prevent voltage sudden change during switching due to excessive voltage fluctuation. At the same time, if the voltage fluctuation is stable during sampling and the average level is maintained in the range of 4.9V to 5.1V, the disconnection time remains unchanged. This adaptive adjustment mechanism effectively avoids false disconnection and test abnormalities caused by hardware state fluctuations.

[0034] In another embodiment, when the voltage signal disconnection period timer reaches 50ms before the adjusted disconnection time, the single-chip microcomputer starts to gradually perform the relay pre-disconnection operation. Specifically, the relays connected to the single-chip microcomputer of each current injection end are put into a pre-disconnection state: under normal voltage output conditions, the relays work according to a pre-set periodic on-off mode, e.g. periodically open and close with an intermittent period of 100ms, reducing voltage loading intensity and preparing for high-voltage switching; if abnormal voltage fluctuation is detected, the relays use a pulse intermittent mode with a duty cycle less than 50%, intermittently applying voltage to reduce the risk of impact. At the same time, the input state of the voltage detection end is kept static, i.e. sampling and voltage change are stopped, to prevent interference signals during switching from affecting test data. The pre-disconnection operation in this stage effectively realizes smooth transition of voltage input, ensuring safety for final disconnection of the relays and high-voltage loading.

[0035] Optionally, the adaptive adjustment of the initial voltage signal disconnection time includes: determining that the voltage output state is abnormal if the difference between the maximum and minimum values of the output level in three consecutive sampling periods exceeds 0.1V, and adjusting the initial voltage signal disconnection time according to the average excess amplitude of the difference to obtain the voltage signal disconnection time; determining that the voltage output state is normal if the average voltage of the voltage output state in consecutive sampling periods is maintained between 4.9V and 5.1V, and taking the initial voltage signal disconnection time as the voltage signal disconnection time.

[0036] In this embodiment, if the voltage signal disconnection period is entered after completing the pin contact detection, the single-chip microcomputer continuously collects the output level of all smart power module pin corresponding voltage detection ends at a sampling period of 10ms, and calculates the deviation between the maximum voltage and the minimum voltage of the sampling values in three consecutive sampling periods If the voltage output state is determined to be abnormal, the difference between the sampled voltage value and the threshold value 0.1V is taken as the over-amplitude. Subsequently, the controller dynamically delays the initial voltage signal disconnection time by over-amplitude x 10ms, for example, if the voltage value is 0.15V, the delay is (0.15V-0.1V) x 10ms = 0.5 x 10ms = 5ms, so that the voltage signal disconnection time is delayed by 5ms, and the new voltage signal disconnection time is reset. Through the above adaptive delay mechanism, the voltage signal disconnection operation is avoided to be completed too early in the abnormal period with large fluctuations, and the stability of the pin voltage state before the relay switching is ensured. In another embodiment, if the single-chip microcomputer continuously samples multiple periods and takes the average value of the detected voltage of each period during the voltage signal disconnection time period, and the average voltage of the continuous 3 sampling periods is stable between 4.9V and 5.1V, the voltage output state is determined to be normal. At this time, the controller does not perform any adjustment operation on the initial voltage signal disconnection time, but directly takes the initial time as the final voltage signal disconnection time. During this process, each current injection end continuously maintains a 5V voltage input to maintain a stable level, and the 5V signal is automatically cut off at the end of the disconnection time period, ensuring that the pin is in a low-voltage state without large fluctuations when the relay is actuated, preventing false jitter before subsequent high-voltage switching, and realizing smooth connection of the low-voltage test to the high-voltage loading step. Optionally, the connection between each current injection end of the pre-disconnection test seat and the single-chip microcomputer includes:

[0037] If the voltage output state is determined to be normal, the state of the electrical connection between the current injection end and the single-chip microcomputer is controlled to be in a periodic on-off state by controlling the relay with a preset intermittent on-off period until the voltage signal disconnection time is reached. If the voltage output state is determined to be abnormal, the on-off state of the current injection end is controlled by controlling the relay with a preset intermittent period, and the voltage is intermittently loaded to the pin end of the intelligent power module in a duty cycle lower than 50% until the voltage signal disconnection time is reached.

[0038]

[0039] ​​​In some embodiments, if the average value of the voltage output state is maintained in the range of 4.9V-5.1V without abnormal fluctuation in the continuous sampling period, the single-chip microcomputer determines that the voltage output state is normal, and controls the relay to drive the connection state between the current injection end and the single-chip microcomputer according to the pre-set intermittent on-off period (for example, on for 100ms and off for 50ms) to make it work in a periodic on-off alternating mode. The specific action flow is: in the on phase, the single-chip microcomputer is allowed to continuously provide a 5V voltage to the smart power module pin through the current injection end to maintain the electrode excitation signal, and in the off phase, the connection is temporarily disconnected to release the parasitic capacitance residual voltage. The periodic on-off control is executed immediately after the pin detection is completed, until the timing reaches the final determined voltage signal disconnection time, to realize the safe control process of smoothly transitioning from continuous low voltage detection to complete low voltage disconnection.

[0040] In another embodiment, if the output voltage fluctuation amplitude in the continuous 3 sampling periods exceeds 0.1V is monitored in the voltage signal disconnection time period, the single-chip microcomputer determines that the voltage output state is abnormal, in order to prevent the high voltage from entering the front pin with unstable contacts and causing impact risk, the relay control strategy of the current injection end is adjusted to a voltage intermittent loading mode with a duty cycle lower than 50% (for example, 20ms high level and 40ms low level). In this control mode, the single-chip microcomputer briefly loads 5V detection voltage to the pin in the high level phase to maintain the electrical path state recognition of the pin; in the low level phase, the loading is cut off to allow the pin interface to dissipate transient voltage and parasitic current. The above intermittent loading is continuously executed in the entire abnormal state until the voltage signal disconnection time, at which time all connections between the current injection end and the single-chip microcomputer are automatically disconnected, providing a voltage fluctuation suppressed hardware interface environment for the high voltage loading step.

[0041] It should be noted that the above high level phase refers to the state that when the relay is in the closed state, a conduction loop is formed between the current injection end and the single-chip microcomputer, so that the 5V direct current voltage can be actually loaded to the smart power module pin, at this time the potential measured at the pin is close to the working voltage (about 4.9-5.1V) of the external power supply side, which is used to maintain the pin path excitation and detection state; the low level phase refers to the state that when the relay is in the open state, the connection between the current injection end and the single-chip microcomputer is cut off, the 5V voltage is no longer loaded to the pin end, and the module pin presents a state of being approximately suspended or gradually decaying from the residual voltage of the pre-grounding stage, at this time the potential rapidly drops to a level range close to 0V or not higher than 0.3V, which is used to release the parasitic capacitance residual charge and form a voltage input interval, thereby reducing the transient voltage impact risk before subsequent high voltage loading.

[0042] Optionally, the insulation performance detection in step S3 comprises: According to the set test parameters, the insulating voltage tester is controlled to load high voltage on the pins of the smart power module, and monitor data of the tester is obtained; According to the monitor data of the tester, a leakage current signal is detected, and the leakage current signal is compared according to a preset current tolerance range. If all pins of the smart power module are within the current tolerance range, it is determined that the insulating performance of the smart power module is a qualified product. If any pin of the smart power module is not within the current tolerance range, it is determined that the insulating performance of the smart power module is a defective product. The smart power modules determined to be qualified products and defective products are integrated to obtain an initial insulating performance detection result.

[0043] In this embodiment, the controller sends a start instruction to the insulating voltage tester according to the preset voltage test parameters (test voltage AC1800V, holding time 3s, leakage current threshold 3mA), so that the high voltage loading path of the output end of the insulating voltage tester is connected to each pin end of the smart power module and the back copper plate in turn, and a complete high voltage path is established. During the test, the internal sampling module of the insulating voltage tester monitors the leakage current change during the high voltage loading process with a sampling period of 5ms, and the sampling data includes timestamp, current peak value and average value. The main control single-chip microcomputer receives the monitoring data in real time and synchronously compares according to the unified time reference recorded at the beginning of the test. The current signal monitored by each pin within the loading holding time is compared with the preset current tolerance range one by one: if the leakage current of all pins is ≤3mA, a qualified determination flag is output; if the leakage current of any pin is >3mA, the pin number and current peak value are immediately recorded, and a defective determination flag is output. Finally, the determination flags of all tested smart power modules are integrated to generate an initial insulating performance detection result list, and the qualified products and defective products are sorted according to the module ID, and are transmitted to the subsequent sorting process.

[0044] Optionally, the method further comprises: Collecting test environment parameters, and identifying environmental impact factors according to the obtained module design material data and test environment parameters; According to the environmental impact factors, identifying the smart power modules in the initial insulating performance detection result that are determined to be defective products due to environmental impact, and correcting the initial insulating performance detection result based on the proportion of pins not within the current tolerance range to obtain an insulating performance detection result.

[0045] In this embodiment, the real-time environmental parameters such as temperature (T), humidity (H), air ionization degree (I) in the test chamber are read by the sensors deployed in the test environment, and the embedded temperature and humidity sensor and the air ion concentration detection probe are used to implement synchronous collection with a period of 2s, and the design material data such as the dielectric constant of the packaging resin material, the surface roughness of the pin metal material, and the pad spacing of the test batch intelligent power module are called to realize multi-source parameter integration input. The control processing core constructs environmental influence factor discriminant conditions according to the dielectric constant of the packaging resin material, the surface roughness of the pin metal material, and the pad spacing, for example, when the temperature and humidity exceed the threshold range (T>35℃ or H>80%) and the distance between the pads d<0.7mm, it is determined as a high-risk environmental mode; if the environment remains in the process recommended interval (T≤35℃ and H≤80%), it is determined as a standard environmental mode. Finally, the environmental influence factor label corresponding to each test batch is output, which is used for subsequent correction work of the insulation detection original result.

[0046] In another embodiment, if the environmental influence factor is identified as a high-risk environmental mode, the control processing core locates the intelligent power module with a defective label in the initial insulation performance detection result, and counts the number of pins that do not pass the tolerance judgment in each module and the total number of pins , calculates the failure proportion ; when between 0.05 and 0.15, the module is identified as a defective product that may be misjudged by environmental factors, and the correction process is executed, and the initial defective product judgment is temporarily marked as a retestable state; if >0.15, the defective product judgment remains unchanged. When the environmental influence factor is a standard environmental mode, all initial detection results remain unchanged. Through the above judgment and correction logic, the environmental parameters, material characteristics, and pin over-limit proportion are integrated to output the final insulation performance detection result, realize accurate optimization of the detection conclusion, and stable improvement of the yield of the production line.

[0047] Optionally, step S5 comprises: assigning a corresponding sorting control instruction to each intelligent power module according to the insulation performance detection result, and sending the sorting control instruction to the sorting machine; After the sorting machine receives the sorting control instruction, the execution component of the sorting machine moves the detected intelligent power module to the corresponding physical position to automatically sort the intelligent power module; display the physical position and insulation performance detection result of each intelligent power module on the display screen.

[0048] In this embodiment, if the insulation performance detection result has been corrected and the detection judgment flag corresponding to each intelligent power module is determined, the single-chip microcomputer traverses the detection result according to the module identification number (for example, ID001-ID200) in sequence, marks the module judged as a qualified product as a classification A instruction, marks the module judged as a defective product as a classification B instruction, and marks the module judged as a retestable state as a retestable C instruction, to construct a sorting control instruction table including the module ID, the instruction type, and the corresponding target physical position index (for example, a qualified area: X1, an NG area: X2). Subsequently, the sorting control instruction is packaged and transmitted in real time to the handler controller through the RS485 bus protocol, so as to keep the actions of the test system and the downstream handler synchronized and reduce the cache retention time.

[0049] In another embodiment, if the handler controller receives the sorting control instruction table from the single-chip microcomputer, the internal execution components including the push rod driver and the slide rail grabbing device moving along the conveying belt are immediately dispatched to position the intelligent power module whose detection has been completed in sequence according to the module ID in the instruction table. When the classification A instruction is identified, the corresponding module is slid into the qualified material receiving groove by driving the push rod. When the classification B instruction is identified, the module is pushed into the defective product collection groove, until the sorting of this batch ends. When the retestable C instruction is identified, the intelligent power module is not directly sorted into the qualified or defective product area, but a retest reflow operation is performed. The sorting process is recorded by the host computer monitoring software at the same time, and the sorting physical position (for example, ID007→qualified area X1, ID035→NG area X2) and the corresponding insulation detection result flag of each module are dynamically displayed on the display screen, so that the operator can intuitively confirm the correctness of the sorting action and record the sorting trace information.

[0050] It is worth noting that the retest reflow operation specifically includes: transferring the module judged as a retestable state to a retest buffer area (for example, an intermediate buffer groove or a retest channel entrance) by a pre-deployed grabbing device, instead of the qualified area or the NG area; the handler simultaneously sends a retest state signal to the host computer, and records the ID and position information of the module; the host computer control logic will trigger the re-entry of the low-voltage detection+high-voltage test process after accumulating a certain number of modules in the retest buffer area (or at the end of the current batch), to re-detect these C instruction modules once. The pre-deployed grabbing device can be various automatic grabbing components such as vacuum suction type manipulator, clamping type mechanical gripper, etc., which can be selected and deployed according to the production line tooling and the packaging structure of the tested module, and the present application does not limit this.

[0051] Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the application file are intended to be included in the present application.

[0052] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application. Therefore, the scope of the application is indicated by the appended claims rather than by the foregoing description, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.

Claims

1. A circuit safety insulation test method for an intelligent power module, characterized in that: The invention is applied to a test socket, which includes a display screen, a sorting machine, a current injection terminal, a controller, a single-chip microcomputer, an insulation withstand voltage tester, a relay electrically connected to the controller, and a gold finger of an integrated voltage detection terminal, wherein the sorting machine, the display screen, the gold finger, the current injection terminal, the single-chip microcomputer, and the insulation withstand voltage tester are all electrically connected to the controller; the method includes the following steps: Step S1: Establishing an electrical connection between the gold finger in the test socket and the intelligent power module, and setting a test connection environment for the test socket to establish the electrical connection, thereby obtaining a test socket connection network; Step S2: Connect the test socket to the voltage detection terminal in the network and connect it to a predetermined voltage to detect the contact status of the pins of each intelligent power module, and set the voltage signal disconnection time according to the pin contact status; Step S3: When the voltage signal disconnection moment arrives, the relay is controlled to disconnect the predetermined voltage, and at the same time, the relay control connection between all current injection terminals in the test socket and the single-chip microcomputer is disconnected; the voltage detection terminal is switched to the high-voltage output terminal of the insulation withstand voltage tester, and the high-voltage loading path is started to perform insulation performance testing; Step S4: sorting defective products according to the insulation performance test results, and displaying the current insulation performance test results and the defective product sorting results on the display screen.

2. The circuit safety insulation testing method of the intelligent power module according to claim 1, characterized in that: Setting the test connection environment in step S1 includes: Summarize and connect all the voltage detection terminals of the gold fingers of the test sockets that have established electrical connections to obtain a unified signal convergence path, and select the positive terminal of the power supply connected to the 5V voltage source and the insulation withstand voltage tester through relay switching to obtain the voltage detection terminal connection network; Connect the current injection terminals of the test sockets that have established electrical connections to a relay, and then connect the other terminals of the relays to the microcontroller to obtain a current injection terminal connection network. The voltage detection terminal connection network and the current injection terminal connection network are integrated to obtain a test socket connection network.

3. The circuit safety insulation testing method of the intelligent power module according to claim 2, characterized in that: The switch selects the positive terminal of the power supply connected to the 5V voltage source and the insulation withstand voltage tester, including: When detecting the contact status of the pins of each intelligent power module, the control relay is turned on, and the voltage detection terminal is connected to the network and connected to the 5V voltage source to form a low-voltage signal path; After all pin contact conditions are detected and confirmed to be normal, set the voltage signal disconnection time, control the relay to disconnect the 5V voltage source connection at the voltage signal disconnection time, and switch the voltage detection end connection network to the positive power supply terminal of the insulation withstand voltage tester to build a high-voltage loading path.

4. The circuit safety insulation testing method of the intelligent power module according to claim 1, characterized in that: Detecting the pin contact status of each intelligent power module in step S2 includes: Based on the feedback from the voltage detection terminal after each current injection terminal is loaded with a 5V voltage signal, the contact between all the gold fingers in the test socket and the pins of the intelligent power module is judged to be good or poor. The judgment of the contact status includes: If the response voltage fluctuation amplitude in the voltage detection terminal feedback within a unit time does not exceed the fluctuation amplitude threshold ±0.1V, the voltage settling time does not exceed the settling time threshold 20ms, and the voltage feedback values ​​of each pin are within the tolerance threshold of 4.9V to 5.1V, then the pin contact of the intelligent power module is judged to be good; If any of the voltage fluctuation amplitude, voltage buildup time, and voltage feedback value of the voltage detection terminal feedback within a unit time exceeds the corresponding threshold, it is determined that the pin of the intelligent power module has poor contact, and the relay is immediately controlled to disconnect the 5V voltage source connection.

5. The circuit safety insulation testing method of the intelligent power module according to claim 1, characterized in that: Setting the voltage signal disconnection time in step S2 includes: Setting a preset transition period from the moment when the current pin contact condition is completed to the moment before high-voltage loading is performed as a voltage signal disconnection period, and determining the specific moment when the voltage signal disconnection period ends as the initial voltage signal disconnection time; During the voltage signal disconnection period, each current injection terminal is controlled to maintain a 5V voltage input, the voltage output state is sampled in real time, and the initial voltage signal disconnection time is adaptively adjusted according to the voltage output state to obtain the voltage signal disconnection time; When the voltage signal disconnection time period reaches 50ms before the voltage signal disconnection moment, each relay is controlled to pre-disconnect the connection between each current injection terminal of the test socket and the microcontroller, and at the same time, the input state of the static voltage detection terminal is kept.

6. The circuit safety insulation testing method of the intelligent power module according to claim 5, characterized in that: Adaptive adjustment of the initial voltage signal disconnection moment includes: The voltage output state is determined to be abnormal when the difference between the maximum and minimum values ​​of the output level in three consecutive sampling periods exceeds 0.1V, and the initial voltage signal disconnection time is adjusted accordingly according to the average over-limit amplitude of the difference to obtain the voltage signal disconnection time; The voltage output state is determined to be normal if the level is maintained between 4.9V and 5.1V in continuous sampling cycles, and the initial voltage signal disconnection time is used as the voltage signal disconnection time.

7. The circuit safety insulation testing method of the intelligent power module according to claim 5, characterized in that: The connections between the current injection terminals of the pre-disconnect test socket and the microcontroller include: If the voltage output state is determined to be normal, the electrical connection state between the current injection terminal and the single chip microcomputer is controlled by controlling the relay to be in a periodic on-off state with a preset intermittent on-off cycle until the voltage signal is disconnected; If the voltage output state is judged to be abnormal, the on-off state of the current injection terminal is controlled by controlling the relay with a preset intermittent period, and the voltage is intermittently loaded to the pin end of the intelligent power module with a duty cycle of less than 50% until the voltage signal is disconnected.

8. The circuit safety insulation testing method of the intelligent power module according to claim 1, characterized in that: The insulation performance test in step S3 includes: According to the set test parameters, control the insulation withstand voltage tester to load the high voltage loading path on the pins of the intelligent power module and obtain the tester monitoring data; Detecting leakage current signals based on tester monitoring data and comparing the leakage current signals according to a preset current tolerance range. If all pins of the intelligent power module are within the current tolerance range, the insulation performance of the intelligent power module is determined to be qualified. If any pin of the intelligent power module is not within the current tolerance range, the insulation performance of the intelligent power module is determined to be defective. The intelligent power modules that are judged as qualified and defective are integrated to obtain the initial insulation performance test results.

9. The circuit safety insulation testing method of an intelligent power module according to claim 1, characterized in that: The method further comprises: Collect test environment parameters and identify environmental influencing factors based on the obtained module design material data and test environment parameters; According to the environmental impact factors, the intelligent power modules judged as defective due to environmental impact in the initial insulation performance test results are identified, and the initial insulation performance test results are corrected based on the proportion of pins that are not within the current tolerance range to obtain the insulation performance test results.

10. The circuit safety insulation testing method of the intelligent power module according to claim 1, characterized in that: Step S5 includes: Assigning a corresponding sorting control instruction to each intelligent power module according to the insulation performance test result, and sending the sorting control instruction to the sorting machine; After receiving the sorting control instruction, the sorting machine drives the execution component of the sorting machine to move the intelligent power modules that have completed the inspection to the corresponding physical position to automatically sort the intelligent power modules; The display screen shows the physical location of each intelligent power module and the insulation performance test results.

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