A press-pack igbt device gate floating failure reproduction system and method

Abstract

The application discloses a kind of crimping IGBT device grid floating failure reproduction system and method, including test main circuit, control loop and monitoring feedback loop;Test main circuit includes: responsible for energizing energizing end, for controlling test main circuit on-off realizes lower bridge, the upper bridge of lower electricity, the upper bridge of the measured end for connecting the lower bridge of the measured crimping IGBT device and current-limiting protection end;Control loop includes signal generator, isolation drive amplification circuit module and relay module, the signal generator generates two-way control signal, respectively input isolation drive amplification circuit module and relay module, isolation drive amplification circuit module is connected with the upper bridge of the measured end, the relay module is connected with the lower bridge of the measured end, and relay module is grounded;The monitoring feedback loop is used for monitoring the high voltage electric signal, current signal and signal generator output signal of test main circuit.The application can realize the controllable failure of crimping IGBT grid floating state.

Description

Technical Field

[0001] This invention relates to the field of power electronics, and in particular to a system and method for reproducing gate floating failure of a press-fit IGBT device. Background Technology

[0002] Currently, my country has built the world's largest power supply system and clean power generation system. For many years, its wind and solar power generation scale has ranked first globally, and its installed capacity of renewable energy has historically surpassed that of coal-fired power. However, the output of new energy sources such as wind and solar power is greatly affected by the environment, is highly intermittent, and suffers from significant transmission losses due to the long distance between power generation sites and loads. Therefore, efficient absorption of new energy sources is a new challenge facing the power grid. Flexible DC transmission (Voltage Source Converter based High Voltage Direct Current transmission, VSC-HVDC) technology, due to its independent control of active and reactive power, low failure rate in commutation, and flexible regulation, has excellent application prospects in weak grids, multi-terminal DC grids, and long-distance high-efficiency transmission grids, and is considered one of the development directions for absorbing large-scale new energy grid connection. IGBTs are the core components for power conversion in flexible DC transmission systems. In the Zhangbei Flexible DC project, which was put into operation in 2020, it is estimated that more than 40,000 press-fit IGBTs were used, 90% of which were imported. In the Guangdong-Hong Kong-Macao Greater Bay Area Flexible DC project, which was put into operation in 2022, the proportion of domestically produced press-fit IGBTs increased to 50% for the first time. If a grid outage is caused by a problem with the press-fit IGBT device, the consequences would be incalculable. Therefore, flexible DC transmission projects place high demands on the quantity and reliability of press-fit IGBT devices. According to international research on DC transmission system failures, the failure of power electronic converters is the primary cause of failures.

[0003] Domestic research on the operational failures of DC transmission converter valves indicates that 84% of converter valve failures originate from converter valve component failures, and among these component failures, 34% are attributed to power devices. Currently, the mainstream power devices used in flexible DC converter valves are typically IGBTs, highlighting the crucial role of IGBT reliability in the safe and stable operation of flexible DC converter valves and the entire flexible DC transmission system. Current research on the failure of press-fit IGBT devices primarily focuses on device aging and its simulation process. Common failure modes include fretting wear, micro-ablation, spring failure, gate oxide layer failure, boundary warping, and open-circuit and short-circuit failures. These failure modes often occur in the later stages of the product lifecycle and during the aging phase. However, newly constructed flexible DC transmission projects using domestically produced press-fit IGBTs often have equipment and devices that have not yet reached the later stages of their product lifecycle or the aging phase due to their late commissioning time. Failures in these cases fall into the category of early-stage failures, and there is currently limited research and mechanistic explanation for these failure modes. To improve the reliability and maintainability of flexible DC transmission projects, help quickly locate faults on-site, and facilitate the resolution of subsequent engineering quality issues, it is essential to clarify the early failure modes and mechanisms of press-fit IGBTs under flexible DC grid conditions. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a system and method for reproducing gate floating failure of a press-fit IGBT device, which reproduces the gate floating failure mode by controlling the gate state of the press-fit IGBT.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A gate floating failure reproduction system for a press-fit IGBT device includes a test main circuit, a control circuit, and a monitoring feedback circuit.

[0007] The main test circuit includes: a power supply terminal responsible for power supply, an upper bridge test terminal for controlling the on / off state of the main test circuit to realize the power-on and power-off of the lower bridge, a lower bridge test terminal for connecting the pressure-connected IGBT device under test, and a current limiting protection terminal.

[0008] The control loop includes a signal generator, an isolation drive amplifier circuit module, and a relay module. The signal generator generates two control signals, which are respectively input to the isolation drive amplifier circuit module and the relay module. The isolation drive amplifier circuit module is connected to the upper bridge test terminal, and the relay module is connected to the lower bridge test terminal. The relay module is grounded.

[0009] The monitoring feedback loop is used to monitor the high-voltage electrical signal, current signal, and output signal of the signal generator in the main test circuit.

[0010] Furthermore, the connection method of the main test circuit is as follows:

[0011] The power supply end, current limiting protection end, lower bridge test end, and upper bridge auxiliary test end are connected in sequence.

[0012] Furthermore, the power supply terminal is a high-voltage power supply or a high-voltage capacitor bank.

[0013] Furthermore, the current limiting protection terminal is an adjustable protection resistor.

[0014] Furthermore, the monitoring feedback loop includes a high-voltage differential probe, a current loop, a passive probe, and an oscilloscope. The high-voltage differential probe and the current loop are used to monitor the voltage and current signals of the main circuit. The signal generator is connected to the oscilloscope through the passive probe.

[0015] Furthermore, the relay module is specifically an Omron miniature relay.

[0016] Furthermore, the pressure-fit IGBT device under test is held in place by a pressure clamp.

[0017] Furthermore, the pressure clamp is a bench vise.

[0018] Furthermore, the upper bridge test terminal serves as the upper bridge switch in the main test circuit and is composed of MOSFET or IGBT.

[0019] A reproduction method based on the aforementioned gate floating failure reproduction system for press-fit IGBT devices includes:

[0020] Test preparation status:

[0021] The upper bridge test terminal is in the blocking state, and the lower bridge test terminal is in the grounding state. At this time, the voltage of the entire test main circuit is on the upper bridge test terminal. The voltage of the upper bridge test terminal is equal to the output voltage of the power supply terminal, and there is no current in the test circuit.

[0022] Test in progress:

[0023] The signal generator outputs two sets of signals. One set of signals is output to the relay module, causing the relay module to change from a closed state to an open state. At this time, the gate of the IGBT at the test terminal of the lower bridge is in a floating state.

[0024] Another set of signal output isolation drive amplifier circuit modules makes the upper bridge test terminal change from the original blocked state to the open state.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] The failure reproduction system of this invention can achieve controllable failure of the gate floating state of a press-fit IGBT by adjusting the energy of the high-voltage capacitor, the protective load resistor, and the power-on and power-off time, which facilitates the study of its gate floating failure mechanism. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of the gate floating failure reproduction system for the press-fit IGBT device of the present invention;

[0028] Figure 2 This is a schematic diagram of the isolated drive amplifier circuit module of the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0030] Example

[0031] like Figure 1 As shown, a gate floating failure reproduction system for a press-fit IGBT device includes a test main circuit, a control circuit, and a monitoring feedback circuit.

[0032] The main test circuit is the core component, comprising a power supply terminal, an upper bridge test terminal, a lower bridge test terminal, and a current limiting protection terminal. The power supply terminal is a high-voltage DC power supply or a high-voltage capacitor bank. The upper bridge test terminal is a high-voltage, high-current IGBT module, and the lower bridge is powered on and off by controlling the on / off state of the control circuit.

[0033] The test terminal of the lower bridge is equipped with a pressure-connected IGBT device, which is placed in a pressure fixture. The current-limiting protection terminal is a high-voltage, high-current, high-power adjustable resistor used for protection of the power supply terminal in the main circuit of the electrical appliance and the test terminal of the upper bridge.

[0034] Further explanation: The power supply is a high-voltage power source and a high-voltage capacitor bank.

[0035] The current limiting protection terminal is a high-voltage, high-power adjustable resistor, which serves as a passive protection element in the main test circuit. It is responsible for preventing the main circuit from entering a power short-circuit state during testing, thereby damaging the high-voltage power supply and high-voltage capacitor bank.

[0036] The upper bridge test terminal is a high-power semiconductor device, which serves as the upper bridge switch of the test circuit. It is generally composed of MOSFET or IGBT and is responsible for controlling the actual power-on process.

[0037] The main test circuit also includes a driver circuit board, which is powered by an independent switching power supply and controls and drives high-power semiconductor devices by receiving signals from the signal generator. The driver circuit board also provides reliable electrical isolation for the signal generator. An interface is reserved at the location of the high-voltage, high-power adjustable resistor in the main circuit circuit board. By measuring the voltage at this location and linking it to the driver circuit board, active protection of the main circuit can be achieved.

[0038] The control loop is responsible for controlling the actions of the upper and lower bridges, and also reserves an input for active protection signals. It includes a signal generator, an isolation drive amplifier circuit module, and a relay module. The signal generator generates two control signals, which are respectively input to the isolation drive amplifier circuit module and the relay module. The isolation drive amplifier circuit module is connected to the upper bridge test terminal, and the relay module is connected to the lower bridge test terminal. The relay module is grounded.

[0039] The signal generator used in this invention has two channels, allowing manual or programmatic control of the upper and lower bridge IGBTs. Since the focus is on the failure behavior of press-fit IGBT sub-units in a gate-floating state, the tested sample only has two states: grounded or floating. Therefore, by adding a miniature relay capable of physical isolation to the gate grounding circuit of the lower bridge tested sample, the switching between the grounded and floating states can be achieved. The Omron miniature relay used in the relay module of this invention has low drive voltage and current, and can be directly driven by the signal generator.

[0040] For the IGBT power devices used in the bridge test terminal, with a rated on-state voltage of 15V and a rated off-state voltage of 0V, the peak drive current during operation can be given by the following empirical formula:

[0041]

[0042] In the formula U ge,max and U ge,min R represents the maximum and minimum gate voltages. G,ext With R G,intHere, represents the external and internal gate resistance values, and 0.74 is an empirically derived attenuation coefficient. Typically, the sum of the external and internal gate resistances is within a few ohms, and the extreme difference in gate voltage is between 10 and 30V. Therefore, the drive current will be from several hundred milliamps to several amps, and the drive power will be tens of watts. Such high drive current and power cannot be directly driven by the signal generator; therefore, the control signal from the signal generator needs to be amplified by an amplifier circuit module before driving the power module. Simultaneously, since the electrical signal in the main test circuit can reach several kilovolts, it may interfere with or even damage the drive signal and circuit during the experiment. Therefore, the signal connected to the main circuit device also needs to be isolated. Based on these requirements, the circuit diagram of the designed isolated drive amplifier circuit module is shown below. Figure 2 As shown in the figure. R2 and R3 are the gate turn-on and turn-off resistors. By adjusting these two resistors, the power-on speed of the upper bridge IGBT module can be changed, thereby affecting the dV / dt of the lower bridge test sample.

[0043] The monitoring feedback loop is used to monitor the high-voltage electrical signal, current signal, and output signal of the signal generator in the main test circuit.

[0044] This includes high-voltage differential probes, passive probes, current loops, and oscilloscopes.

[0045] The high-voltage differential probe and current loop mainly monitor the high-voltage electrical signal and the corresponding current signal in the main circuit. The passive probe is placed on the output signal of the signal generator and used as the trigger signal of the oscilloscope.

[0046] Further explanation: The pressure-fit IGBT device under test is held in place by a pressure clamp. The pressure clamp comprises a vise, a fiberglass board or bakelite, an aluminum block, a limiting frame, and a gate contact plate. A pressure sensor is also included to confirm the applied pressure. By rotating the screw of the vise, the components can be tightly pressed together. The fiberglass board or bakelite provides insulation and heat protection, requiring a minimum withstand voltage of 5000V and a temperature of 200℃. The aluminum block is the main component for electrical connection and pressure transmission. It has positioning holes on its top and bottom surfaces for fixing the limiting frame, a central liquid cooling channel, and pagoda-shaped connectors on both sides for connecting to a liquid cooler, facilitating temperature control of the device's operating environment during environmental testing.

[0047] A method for reproducing gate floating failure in a press-fit IGBT device is as follows:

[0048] Test preparation status:

[0049] The upper bridge test terminal is in the blocking state, and the lower bridge test terminal is in the grounding state. At this time, the voltage of the entire test main circuit is on the upper bridge test terminal. The voltage of the upper bridge test terminal is equal to the output voltage of the power supply terminal, and there is no current in the test circuit.

[0050] Test in progress:

[0051] The signal generator outputs two sets of signals. One set of signals is output to the relay module, causing the relay module to change from a closed state to an open state. At this time, the gate of the IGBT at the test terminal of the lower bridge is in a floating state.

[0052] Another set of signal output isolation drive amplifier circuit modules makes the upper bridge test terminal change from the original blocked state to the open state.

[0053] The specific operations in this embodiment are as follows:

[0054] The high-voltage power supply and high-voltage capacitor bank output voltage were set to 1000V, the bridge gate turn-on / turn-off resistance was 6Ω-6Ω, the lower bridge power-on time was 20μs, and the lower bridge gate remained floating. The load resistance was gradually reduced from 40Ω to 0Ω, and the device was rendered unusable by reducing the protective load resistance Rload. Waveforms were obtained for Rload = 40Ω, 30Ω, 20Ω, 13Ω, and 0.4Ω. This indicates that the device successfully prepared a failed IGBT sample with a floating gate and pressure connection by reducing the protective load resistance.

[0055] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A system for reproducing gate floating failure in a press-fit IGBT device, characterized in that, This includes testing the main circuit, control circuit, and monitoring feedback circuit; The main test circuit includes: a power supply terminal responsible for power supply, an upper bridge test terminal for controlling the on / off state of the main test circuit to realize the power-on and power-off of the lower bridge, a lower bridge test terminal for connecting the pressure-connected IGBT device under test, and a current limiting protection terminal. The control loop includes a signal generator, an isolation drive amplifier circuit module, and a relay module. The signal generator generates two control signals, which are respectively input to the isolation drive amplifier circuit module and the relay module. The isolation drive amplifier circuit module is connected to the upper bridge test terminal, and the relay module is connected to the lower bridge test terminal. The relay module is grounded. The monitoring feedback loop is used to monitor the high-voltage electrical signal, current signal, and output signal of the signal generator in the main test circuit. The connection method of the main test circuit is as follows: The power supply end, current limiting protection end, lower bridge test end, and upper bridge auxiliary test end are connected in sequence; The power supply is a high-voltage power supply or a high-voltage capacitor bank; The current limiting protection terminal is an adjustable protection resistor; The monitoring feedback loop includes a high-voltage differential probe, a current loop, a passive probe, and an oscilloscope. The high-voltage differential probe and the current loop are used to monitor the voltage and current signals of the main test circuit. The signal generator is connected to the oscilloscope through the passive probe. The upper bridge test terminal serves as the upper bridge switch in the main test circuit and is composed of MOSFET or IGBT.

2. The gate floating failure reproduction system for press-fit IGBT devices according to claim 1, characterized in that, The relay module is specifically an Omron miniature relay.

3. The gate floating failure reproduction system for press-fit IGBT devices according to claim 1, characterized in that, The pressure-fit IGBT device under test is held in place by a pressure clamp.

4. The gate floating failure reproduction system for press-fit IGBT devices according to claim 3, characterized in that, The pressure clamp is a bench vise.

5. A method for reproducing gate floating failure of a press-fit IGBT device based on any one of claims 1-4, characterized in that, include: Test preparation status: The upper bridge test terminal is in the blocking state, and the lower bridge test terminal is in the grounding state. At this time, the voltage of the entire test main circuit is on the upper bridge test terminal. The voltage of the upper bridge test terminal is equal to the output voltage of the power supply terminal, and there is no current in the test circuit. Test in progress: The signal generator outputs two sets of signals. One set of signals is output to the relay module, causing the relay module to change from a closed state to an open state. At this time, the gate of the IGBT at the test terminal of the lower bridge is in a floating state. Another set of signal output isolation drive amplifier circuit modules makes the upper bridge test terminal change from the original blocked state to the open state.

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