Dual protection system of IGBT testing device and application method thereof

Abstract

The application provides a double protection system of an IGBT testing device and an application method thereof, which comprises: a main circuit, a main circuit power module and a measured module; the main circuit power module is electrically connected with the measured module to form the main circuit; a cut-off protection module is arranged in series on the main circuit to serve as a main circuit energy cut-off switch; a release protection module is connected in parallel across the two ends of the measured module; a detection signal processing module comprises a signal processing unit and a detection unit which are electrically connected; the signal processing unit is electrically connected with the cut-off protection module and the release protection module to make corresponding protection actions according to the obtained current signal. The cut-off protection module and the release protection module can withstand short-circuit fault impact, realize double protection, and greatly reduce the safety hidden danger caused by the discharge of the measured module in the short-circuit failure moment.

Description

Technical Field

[0001] This invention relates to the field of device testing equipment technology, and in particular to a dual protection system for IGBT testing equipment and its application method. Background Technology

[0002] The protection scheme for IGBT test equipment is a multi-layered, integrated hardware and software system. Its core objective is to quickly and reliably disconnect the energy circuit in the event of an anomaly in the equipment itself or the device under test (DUT), preventing equipment damage, device explosion, or even personal injury. Existing IGBT testing equipment protection solutions have the following shortcomings: 1. It only uses cut-off protection, which has a single protection function. It only cuts off the main circuit energy storage capacitor and has no parallel discharge branch. When the series IGBT is turned off, the stray inductance of the line generates an extremely high induced voltage spike, which can easily break down the DUT and the protection module itself.

[0003] 2. Lack of sustainability: If fuses and mechanical contactors are used for protection, fuses are disposable consumables, and the cost of mass production, testing and maintenance is high; contactors operate for hundreds of microseconds, which cannot meet the needs of microsecond-level ultra-fast protection. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a dual protection system for IGBT testing equipment and its application method. The system includes a cut-off protection module and a release protection module, which can withstand short-circuit fault impacts, achieve dual protection, and significantly reduce the safety hazards caused by short-circuit discharge of the high-voltage busbar energy storage capacitor.

[0005] The embodiments of the present invention are achieved through the following technical solutions: A dual protection system for IGBT testing equipment includes: The main circuit includes a main power module and a module under test; the main power module and the module under test are electrically connected to form the main circuit. Cut-off protection module; the cut-off protection module is arranged in series on the main circuit to serve as a main circuit energy cut-off switch; Release protection module; the release protection module is connected in parallel across the two ends of the module under test and is arranged close to the main power supply module; A detection signal processing module; the detection signal processing module includes a signal processing unit and a detection unit that are electrically connected, and the detection end of the detection unit is connected to the main circuit to acquire the main circuit current signal in real time; The signal processing unit is electrically connected to the cut-off protection module and the release protection module respectively. The signal processing unit controls the cut-off protection module and the release protection module to perform corresponding protection actions according to the acquired current signal.

[0006] According to a preferred embodiment, the cutoff protection module includes an IGBT cutoff protection unit. The release protection module includes an IGBT release protection unit.

[0007] According to a preferred embodiment, both the IGBT cutoff protection unit and the IGBT release protection unit include an auxiliary power supply unit, a bias power supply unit, an overvoltage clamping protection unit, a logic control unit, and an isolation drive shutdown unit.

[0008] According to a preferred embodiment, the auxiliary power supply unit includes an IR2085S push-pull isolated power supply; The bias power supply section includes an IGBT gate drive bias power supply, which includes a plurality of parallel capacitors. The overvoltage clamping protection unit includes a series TVS clamping protection; The logic control unit includes a photoelectric sensor and a tri-state buffer; The isolation drive shutdown section includes a high-speed optocoupler driver, a Darlington push-pull mechanism, and a drive resistor.

[0009] According to a preferred embodiment, the module under test includes a DUT driving unit and a device under test (DUT).

[0010] According to a preferred embodiment, the gate drive turn-on voltage V1 of the IGBT gate drive bias power supply is +VG, which can be adjusted according to different module parameters. The gate drive turn-off voltage V2 of the IGBT gate drive bias power supply is at the -VG terminal, which can be adjusted according to different module parameters. The gate resistance of the IGBT gate drive bias power supply is 1.57Ω, which is composed of three 4.7Ω resistors connected in parallel. The IGBT gate drive bias power supply has a 1.57Ω gate resistor, which is composed of three 4.7Ω resistors connected in parallel.

[0011] According to a preferred embodiment, the main power module includes a charging / discharging power supply and a busbar energy storage capacitor.

[0012] A method for applying a dual protection system for an IGBT testing device includes the following steps: In step S100, the normal test condition cutoff protection module is kept on, and the busbar energy storage capacitor outputs test current to the device under test (DUT). Step S200: Release the protection module to keep it off, so as not to affect the normal test waveform and accuracy; In step S300, the detection unit monitors the main circuit current in real time, and the detection signal processing module outputs a fault-free signal after the fault-free condition is reached. Step S400: When a short circuit or overcurrent fault occurs in the main circuit, the detection unit is triggered to identify the current change and immediately outputs a fault level to drive the cut-off protection module and the release protection module. The release protection module is turned on first to release the parallel branch to absorb part of the bus current flowing through the module under test, so as to protect the module under test. Then the cut-off protection module cuts off the series main circuit. The already opened release protection module reduces the induced high voltage spike generated by the inductance after the cut-off protection module is turned off, so as to protect the cut-off protection module. In step S500, the detection unit sends a fault signal to notify the signal processing unit to control the main power supply module to charge and discharge, discharge the remaining energy stored in the busbar energy storage capacitor, clear the fault mark, disconnect the protection module to restore the conduction of the series branch, and release the protection module to restore the shutdown of the parallel branch.

[0013] According to a preferred embodiment, step S400 includes steps S4001 and S4002. Step S4001: Release the protection module to discharge the parallel branch, and fully conduct within 1μs, absorb the set value of current, reduce the current flowing through the device under test (DUT), and protect the DUT and the fixture. Step S4002: After a 200ns delay inside the driver, the cut-off protection module controls the series branch to be completely shut down within 1.2μs, completely cutting off the continuous energy feed from the main power module to the fault circuit, thus terminating the energy supply for the main circuit short circuit from the source.

[0014] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects: This invention is equipped with a cut-off protection module and a release protection module. The above two modules respectively realize dual protection of energy storage head cut-off and load end energy storage discharge. It can withstand the impact of short circuit faults, and the dual blocking of fault energy release significantly reduces the safety hazards caused by short circuit discharge of high voltage busbar energy storage capacitors. It eliminates disposable fuses and slow mechanical switches. All components can be reused, have sustainability, and greatly reduce equipment operation and maintenance costs.

[0015] It simultaneously protects two core and valuable components: the busbar energy storage capacitor and the device under test (DUT) fixture, preventing damage to these components and addressing the industry-specific pain point of cascading device failure in high-power testing scenarios. It is highly targeted to specific scenarios. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the circuit structure of a dual protection system for an IGBT testing device provided in an embodiment of the present invention; Figure 2 A schematic diagram of the circuit principle of the truncation protection module provided in an embodiment of the present invention; Figure 3 A schematic diagram of the circuit principle of the release protection module provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the circuit principle of the auxiliary power supply unit provided in an embodiment of the present invention.

[0018] Icons: 1. Main power supply module; 11. Charge / discharge power supply; 2. Module under test; 3. Cut-off protection module; 4. Release protection module; 5. Detection signal processing module. Detailed Implementation

[0019] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0020] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Example

[0022] Reference Figures 1 to 4A dual protection system for an IGBT testing device includes: a main circuit, comprising a main power supply module 1 and a module under test 2; the main power supply module 1 and the module under test 2 are electrically connected to form the main circuit; a cut-off protection module 3; the cut-off protection module 3 is arranged in series on the main circuit to act as a main circuit energy cut-off switch; a release protection module 4; the release protection module 4 is connected in parallel across the two ends of the module under test 2; and a detection signal processing module 5; the detection signal processing module 5 includes an electrically connected signal processing unit and a detection unit, the detection end of the detection unit is connected to the main circuit to acquire the main circuit current signal in real time; the signal processing unit is electrically connected to the cut-off protection module 3 and the release protection module 4 respectively, and the signal processing unit controls the cut-off protection module 3 and the release protection module 4 to perform corresponding protection actions according to the acquired current signal.

[0023] According to a preferred embodiment, the cutoff protection module 3 includes an IGBT cutoff protection unit. Release protection module 4 includes an IGBT release protection unit.

[0024] According to a preferred embodiment, both the IGBT cutoff protection unit and the IGBT release protection unit include an auxiliary power supply unit, a bias power supply unit, an overvoltage clamping protection unit, a logic control unit, and an isolation drive shutdown unit.

[0025] According to a preferred embodiment, the auxiliary power supply section includes an +18V terminal, a -VG terminal, and a +5V terminal for isolation generated by the IR2085S push-pull isolated power supply. The bias power supply section includes a +VG terminal, a -VG terminal, and a large-capacity parallel capacitor to form an IGBT gate drive bias power supply. The bias power supply section includes an IGBT gate drive bias power supply, which includes several parallel capacitors, a +VG terminal, and a -VG terminal. The large-capacity parallel capacitor is composed of multiple parallel capacitors, and the large capacity range includes, but is not limited to, capacitors above 47uF. In this embodiment, a 100uF parallel capacitor can be selected.

[0026] The overvoltage clamping protection unit includes TVS clamping protection connected in series between the GC terminals; The logic control unit includes photoelectric sensors and tri-state buffers; The isolated drive shutdown section includes a high-speed optocoupler driver, a Darlington push-pull mechanism, and a drive resistor, enabling positive and negative gate voltage drive of the IGBT.

[0027] According to a preferred embodiment, the module under test 2 includes a DUT driving unit and a device under test (DUT).

[0028] According to a preferred embodiment, the gate drive turn-on voltage V1 of the IGBT gate drive bias power supply is +VG, which can be adjusted according to different module parameters. The gate drive turn-off voltage V2 of the IGBT gate drive bias power supply is at the -VG terminal, which can be adjusted according to the parameters of different modules used. The turn-on gate resistor of the IGBT gate drive bias power supply is 1.57Ω, which is composed of three 4.7Ω resistors connected in parallel. The IGBT gate drive bias power supply has a 1.57Ω gate resistor, which is composed of three 4.7Ω resistors connected in parallel.

[0029] According to a preferred embodiment, the main power module 1 includes a charging / discharging power supply 11 and a busbar energy storage capacitor.

[0030] A method for applying a dual protection system for an IGBT testing device includes the following steps: In step S100, the normal test condition cutoff protection module 3 is continuously turned on, and the busbar energy storage capacitor outputs test current to the device under test (DUT). Step S200: Release protection module 4 to keep it off, so as not to affect the normal test waveform and accuracy; In step S300, the detection unit monitors the main circuit current in real time, and the detection signal processing module 5 outputs a fault-free signal after the fault-free condition is reached. Step S400: When a short circuit or overcurrent fault occurs in the main circuit, the detection unit is triggered to identify the current change and immediately outputs a fault level to drive the cut-off protection module 3 and the release protection module 4. The release protection module 4 is turned on first to release the parallel branch to absorb part of the bus current flowing through the tested module 2, so as to protect the tested module 2. Then the cut-off protection module 3 cuts off the series main circuit. The already opened release protection module 4 reduces the induced high voltage spike generated by the inductance after the cut-off protection module 3 is turned off, so as to protect the cut-off protection module 3. In step S500, the detection unit sends a fault signal to notify the signal processing unit to control the main power module 1 to charge and discharge, discharge the remaining energy stored in the busbar energy storage capacitor, clear the fault mark, cut off the protection module 3 to restore the series branch conduction, and release the protection module 4 to restore the parallel branch shutdown.

[0031] According to a preferred embodiment, step S400 includes step S4001 and step S4002. Step S4001: Release protection module 4 discharges the parallel branch, fully conducts within 1μs, absorbs the set value of current, reduces the current flowing through the device under test (DUT), and protects the DUT and fixture. Step S4002: After a 200ns delay inside the drive for the same fault level, the cut-off protection module 3 controls the series branch to be completely shut down within 1.2μs, completely cutting off the continuous energy feed from the main power module 1 to the fault circuit, thus terminating the energy supply for the main circuit short circuit from the source.

[0032] Working principle of the invention: In this embodiment, there are an auxiliary power supply unit, a bias power supply unit, an overvoltage clamping protection unit, a logic control unit, and an isolation drive shutdown unit. The auxiliary power supply section includes the IR2085S push-pull isolated power supply and its +18V, -VG, and +5V terminals for generating isolation; the auxiliary power supply section supplies power to the logic control section (logic circuit) and the positive and negative power supplies to the isolated drive shutdown section (drive circuit).

[0033] The bias power supply section includes a +VG terminal, a -VG terminal, and a large-capacity parallel capacitor, providing positive and negative power supplies for IGBT gate drive bias. The large-capacity parallel capacitor can be composed of multiple parallel capacitors, and the large capacity range includes, but is not limited to, capacitors above 47uF. In this embodiment, a 100uF parallel capacitor can be selected.

[0034] The overvoltage clamping protection unit includes the P2 collector and a TVS clamping protection connected in series between GC. When overvoltage occurs, the TVS (ZD1-ZD7) breaks down the IGBT chip in the IGBT release protection unit or the IGBT chip in the IGBT cutoff protection unit, thus preventing the breakdown of the IGBT chip in the IGBT release protection unit or the IGBT chip in the IGBT cutoff protection unit.

[0035] The logic control unit includes a BR-2521 photoelectric sensor and a 74HC125 four-channel tri-state buffer. The photoelectric sensor receives light control signals. The 74HC125 performs signal shaping and amplifies the drive capability. After processing by the logic circuit, the isolated driver optocoupler TLP350 is activated when light is present.

[0036] The isolation drive shutdown section includes a high-speed isolation optocoupler driver of model TLP350, which realizes electrical isolation between the logic section and the drive section. The push-pull circuit composed of Q1 and Q2 outputs amplifies the drive capability. When there is light on the primary side (i.e., 74HC125 outputs a low level), the output of the high-speed isolation optocoupler driver is high, Q1 is turned on, Q2 is turned off, and +VG is applied to the IGBT gate P3, turning on the IGBT. Conversely, when the optocoupler is off, the output of the high-speed isolation optocoupler driver is low, Q1 is turned off, Q2 is turned on, and -VG is applied to the IGBT gate P3, turning off the IGBT chip in the IGBT release protection unit or the IGBT cutoff protection unit.

[0037] The protection effect of this invention is greatly improved. Compared with simple cut-off protection, cutting off and releasing two identical modules reduces the protection time by 20%. Different IGBT modules can be selected according to different needs, resulting in better performance.

[0038] The protection speed is compatible with a wide range of power devices. The 1μs discharge response matches the short-circuit tolerance limit of SiC devices, and the 1.2μs cutoff takes into account the driving stability of high-power IGBT modules. It will not cause damage to the protection tube itself due to the extremely fast turn-off. No consumables required, reusable, both circuits use commercial high voltage and high current IGBT power modules, which can withstand tens of thousands of short circuit faults, saving the labor and material costs of frequent fuse replacements. The circuit is simple and has strong anti-interference capabilities. It uses a single analog current detection unit and achieves hierarchical timing by relying on simple drive delay. It does not require complex digital timing control and works stably under high-power pulse test environment. With dual energy isolation, the residual energy is first released, and then the energy storage is cut off, thus doubly blocking the release of fault energy and significantly reducing the safety hazards caused by short-circuit discharge of the high-voltage busbar energy storage capacitor.

[0039] Both the IGBT cutoff protection unit and the IGBT release protection unit in this application share the common characteristics of IGBTs. IGBTs have a faster turn-on speed than turn-off speed, and the addition of release protection enables faster protection. In this embodiment, the fixture is customized for different Device Under Test (DUTs). Each fixture corresponds to a DUT. Unless otherwise specified in this embodiment, the fixture can be equivalent to or a combination of parts of the DUT. When the DUT fails or the main circuit is short-circuited, the equipment and fixture can be protected, preventing further damage.

[0040] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A dual protection system for an IGBT testing device, characterized in that, include: The main circuit includes a main power module and a module under test; the main power module and the module under test are electrically connected to form the main circuit. Cut-off protection module; The cut-off protection module is arranged in series on the main circuit to serve as a main circuit energy cut-off switch; Release protection module; the release protection module is connected in parallel across the two ends of the module under test and is arranged close to the main power supply module; A detection signal processing module; the detection signal processing module includes a signal processing unit and a detection unit that are electrically connected, and the detection end of the detection unit is connected to the main circuit to acquire the main circuit current signal in real time; The signal processing unit is electrically connected to the cut-off protection module and the release protection module respectively. The signal processing unit controls the cut-off protection module and the release protection module to perform corresponding protection actions according to the acquired current signal.

2. The dual protection system of the IGBT testing equipment according to claim 1, characterized in that, The cutoff protection module includes an IGBT cutoff protection unit. The release protection module includes an IGBT release protection unit.

3. The dual protection system of the IGBT testing equipment according to claim 2, characterized in that, Both the IGBT cutoff protection unit and the IGBT release protection unit include an auxiliary power supply unit, a bias power supply unit, an overvoltage clamping protection unit, a logic control unit, and an isolation drive shutdown unit.

4. The dual protection system of the IGBT testing equipment according to claim 3, characterized in that, The auxiliary power supply unit includes a push-pull isolated power supply; The bias power supply section includes an IGBT gate drive bias power supply, which includes a plurality of parallel capacitors. The overvoltage clamping protection unit includes a series TVS clamping protection; The logic control unit includes a photoelectric sensor and a tri-state buffer; The isolation drive shutdown section includes a high-speed optocoupler driver, a Darlington push-pull mechanism, and a drive resistor.

5. The dual protection system of the IGBT testing equipment according to claim 3, characterized in that, The module under test includes a DUT driver unit and a device under test (DUT).

6. The dual protection system of the IGBT testing equipment according to claim 4, characterized in that, The gate drive turn-on voltage V1 of the IGBT gate drive bias power supply is +VG. The gate drive turn-off voltage V2 of the IGBT gate drive bias power supply is -VG terminal. The gate resistance of the IGBT gate drive bias power supply is 1.57Ω. The turn-off gate resistor of the IGBT gate drive bias power supply is 1.57Ω.

7. The dual protection system of the IGBT testing equipment according to claim 1, characterized in that, The main power module includes a charging / discharging power supply and a busbar energy storage capacitor.

8. The dual protection system of the IGBT testing equipment according to claim 4, characterized in that, The push-pull isolated power supply is model IR2085S.

9. A method for applying a dual protection system for an IGBT testing device, comprising using the dual protection system for the IGBT testing device as described in any one of claims 1 to 8, characterized in that, Specifically, the following steps are included: In step S100, the normal test condition cutoff protection module is kept on, and the busbar energy storage capacitor outputs test current to the device under test (DUT). Step S200: Release the protection module to keep it off, so as not to affect the normal test waveform and accuracy; In step S300, the detection unit monitors the main circuit current in real time, and the detection signal processing module outputs a fault-free signal after the fault-free condition is reached. Step S400: When a short circuit or overcurrent fault occurs in the main circuit, the detection unit is triggered to identify the current change and immediately outputs a fault level to drive the cut-off protection module and the release protection module. The release protection module is turned on first to release the parallel branch to absorb part of the bus current flowing through the module under test, so as to protect the module under test. Then the cut-off protection module cuts off the series main circuit. The already opened release protection module reduces the induced high voltage spike generated by the inductance after the cut-off protection module is turned off, so as to protect the cut-off protection module. In step S500, the detection unit sends a fault signal to notify the signal processing unit to control the main power supply module to charge and discharge, discharge the remaining energy stored in the busbar energy storage capacitor, clear the fault mark, disconnect the protection module to restore the conduction of the series branch, and release the protection module to restore the shutdown of the parallel branch.

10. The application method of the dual protection system of the IGBT testing equipment according to claim 9, characterized in that, Step S400 includes steps S4001 and S4002; Step S4001: Release the protection module to discharge the parallel branch, and fully conduct within 1μs, absorb the set value of current, reduce the current flowing through the device under test (DUT), and protect the DUT. Step S4002: After a 200ns delay inside the driver, the above fault level is completely shut off within 1.2μs by the control of the cut-off protection module, thus completely cutting off the continuous energy feed from the main power module to the fault circuit and terminating the energy supply for the main circuit short circuit from the source.

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