Multi-chip IGBT module chip branch defect monitoring method and circuit based on gate peak current

Abstract

The invention discloses a multi-chip IGBT module chip branch defect monitoring method and circuit based on gate pole peak current, and the monitoring circuit comprises a driving circuit which is used for controlling the on and off of an IGBT module; the current sampling circuit is used for obtaining a gate current of the IGBT module in the opening process, converting the obtained gate current into a synchronously changing voltage signal and outputting the voltage signal to the peak value monitoring circuit; and the peak value monitoring circuit is used for monitoring the gate pole peak current. According to the invention, under the condition that the IGBT module is not disassembled, the chip branch state of the IGBT module can be obtained; the monitoring method is easy to measure, short pulse gate peak current information serving as a transient quantity can be converted into a stable direct-current signal serving as a steady-state quantity, meanwhile, the sampling frequency is reduced, the cost is reduced, and the potential of real-time online monitoring is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of IGBT module monitoring, and in particular to a method and circuit for monitoring chip branch defects of a multi-chip IGBT module based on gate peak current. Background Art

[0002] Power electronic devices are widely used in energy production, transmission and consumption systems due to their high efficiency. Semiconductor power devices are the most vulnerable components in power electronic converters, and the reliability of power electronic devices is closely related to the reliability of the entire power electronic system. Therefore, in order to improve the reliability of power electronic systems, the reliability of semiconductor power devices in power converters must be studied. As a commercial general-purpose power semiconductor device, IGBT is widely used in power electronic systems with a wide power level. In order to improve the current capacity of the module and reduce the cost of use, the IGBT module with a multi-chip parallel structure packaged by bonding wires is considered to be a promising solution to increase the capacity of power modules. However, complex and harsh working conditions and alternating thermal-mechanical stress make IGBT modules one of the devices that are extremely prone to aging and damage in power electronic systems. Due to the different thermal expansion coefficients between the material layers of the module, bonding wire fatigue failure will occur under alternating stress, resulting in the failure of the module's electrical function. By monitoring the gate-level current changes, the state monitoring of the internal bonding wire defects of the IGBT module can be achieved.

[0003] The existing methods for monitoring the defects of the bonding wires inside IGBT modules mainly include direct monitoring and indirect monitoring. Among them, the most commonly used indirect monitoring is the contactless eddy current pulse thermal imaging technology, but they require special testing equipment and are difficult to apply in practice. At present, for the direct monitoring of the defects of the bonding wires inside IGBT modules, a variety of state monitoring methods have been proposed at home and abroad. However, these methods have certain limitations in the monitoring of the bonding wire state of high-power multi-chip IGBT modules. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a multi-chip IGBT module chip branch defect monitoring method and circuit based on gate peak current, so that the chip branch status of the IGBT module can be obtained without disassembling it, and it is easy to measure. It can convert the short pulse gate peak current information as a transient quantity into a stable DC signal as a steady-state quantity, while reducing the sampling frequency and cost, and has the potential for real-time online monitoring.

[0005] The technical solution adopted by the present invention is:

[0006] A multi-chip IGBT module chip branch defect monitoring method based on gate peak current. Since the gate peak current of the IGBT module during the switching process will be affected by the changes in its internal parameters due to the aging of the IGBT module, the current health status of the IGBT module can be evaluated by monitoring the gate peak current of the IGBT module during the switching process.

[0007] Since the IGBT module needs to withstand the thermal mechanical stress generated by the power cycle, it will age and its internal parameters or structure will change, which will gradually reduce the safety and reliability of the IGBT module. At the same time, the gate peak current of the IGBT module during the switching process will also change, which provides conditions for the health status monitoring of the IGBT module. This solution collects and processes the gate peak current during the switching process of the IGBT module, and can be easily monitored without disassembling the IGBT module, ensuring that the IGBT module works under normal conditions while accurately evaluating its health status, thereby improving the safety and reliability of the module and system.

[0008] A multi-chip IGBT module chip branch defect monitoring method based on gate peak current takes the IGBT module gate peak current as the monitoring object and evaluates the current IGBT module chip branch defect situation by continuously comparing the changes in gate peak current obtained under multiple switching cycles.

[0009] A multi-chip IGBT module chip branch defect monitoring method based on gate peak current. Since the chip branch defects of the IGBT module will change the internal parameters of the IGBT module, causing the gate peak current of the IGBT module to change during the turn-on and turn-off processes, the gate peak current of the IGBT module during the turn-on process can be monitored to monitor the chip branch defects of the IGBT module.

[0010] A monitoring circuit for implementing the above-mentioned multi-chip IGBT module chip branch defect monitoring method based on gate peak current includes:

[0011] A drive circuit for controlling the on and off of the IGBT module;

[0012] The current sampling circuit is used to obtain the gate current of the IGBT module during the turn-on process, and convert the obtained gate current into a synchronously changing voltage signal and output it to the peak monitoring circuit;

[0013] The peak monitoring circuit is used to monitor the gate peak current.

[0014] The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current also includes a microprocessor for generating an input control signal Si2. The current sampling circuit receives the input control signal Si2, and monitors the gate current obtained by the current sampler when the input control signal Si2 is at a high level to obtain gate peak current information. The circuit is reset when the input control signal Si2 is at a low level. When the input control signal Si2 is maintained at a high level in each switching cycle, the peak detection circuit can also compare the gate peak current.

[0015] In this way, the input control signal Si2 is used to control whether to collect the gate peak current of the IGBT module, so as to monitor the defect status of the IGBT module chip branch according to the monitoring needs. At the same time, by keeping the input control signal Si2 at a high level in multiple switching cycles, the current collection circuit collects the gate peak current of multiple switching cycles, and compares the gate peak current information, so as to achieve the purpose of monitoring the defect status of the IGBT module chip branch.

[0016] A multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, wherein the microprocessor is also used to generate an input control signal Si1, which is used to control the normal opening and closing of the IGBT module through a driver, and controls the IGBT module to be turned on when the input control signal Si1 is at a high level, and controls the IGBT module to be turned off when the input control signal Si1 is at a low level.

[0017] The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current also includes:

[0018] An isolated power supply circuit, whose output ends are respectively connected to the drive circuit, the current sampling circuit and the peak monitoring circuit, and is used to supply power to the drive circuit, the current sampling circuit and the peak monitoring circuit;

[0019] The current sampling circuit includes a current sampler, an emitter follower, a signal switching unit and a signal operation unit. The emitter follower is connected to the output end of the current sampler and is used to output the voltage signal output by the current sampler to the signal switching unit; the signal switching unit is used to receive the voltage signal or the ground signal output by the emitter follower, and output the voltage signal to the signal operation unit when receiving the voltage signal; the signal operation unit is used to receive the voltage signal output by the signal switching unit, and output the voltage signal to the peak monitoring circuit after performing operation processing on the voltage signal.

[0020] In this way, when the monitoring circuit of the present invention is used, the driving circuit controls the IGBT module to turn on. At this time, the current sampler will output a voltage signal that changes synchronously with the gate current to the emitter follower; the emitter follower receives the voltage signal output by the current sampler, and outputs the voltage signal to the signal switching unit. The signal switching unit outputs the received voltage signal or the ground signal to the signal operation unit. The signal operation unit performs operation processing on the received voltage signal and outputs it to the peak monitoring circuit. The peak monitoring circuit receives the voltage signal output by the signal operation unit, and keeps the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit; because the voltage signal output by the current sampler changes synchronously with the gate current, and the gate peak current contains the information of the IGBT module chip branch defect, the voltage on the capacitor C10 finally also contains the information of the IGBT module chip branch defect, so the voltage U on the capacitor C10 is used to monitor the voltage signal output by the current sampler. C10 It can be used to characterize IGBT module chip branch defects.

[0021] The monitoring circuit of the present invention can not only ensure the normal operation of the IGBT module, but also perform monitoring without disassembling the IGBT module, and has the potential for real-time online monitoring. At the same time, the monitoring circuit has high integration, and the monitoring method is easy to implement. At the same time, it can convert the short-pulse gate peak current information as a transient quantity into a smooth DC signal as a steady-state quantity, thereby reducing the sampling frequency, reducing the cost, and accurately evaluating the aging state of the IGBT module, thereby improving the safety and reliability of the IGBT module and the system having the IGBT module, and has practical application value.

[0022] A multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, wherein the signal switching unit in the current sampling circuit receives the input control signal Si2 issued by the microprocessor, and can output a voltage signal that changes synchronously with the gate current to the signal operation unit when the input control signal Si2 is at a high level, and the voltage signal is output to the peak monitoring circuit via the signal operation unit, and the peak monitoring circuit compares the voltage signal with the voltage across the capacitor C10, thereby performing a state monitoring process; and the signal switching unit in the current sampling circuit resets the charge of the capacitor C10 when the input control signal Si2 is at a low level, and the state monitoring ends.

[0023] Thus, when monitoring is performed, the microprocessor sends an input control signal Si2 at a high level. At the same time, when the input control signal Si1 sent by the microprocessor is also at a high level, the drive circuit will control the IGBT module to turn on. The signal switching unit in the current sampling circuit further outputs the voltage signal received from the emitter follower output to the signal operation unit, and the peak monitoring circuit keeps the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit; the voltage U on the capacitor C10 is C10 The voltage U on capacitor C10 is collected. C10 To characterize the defect status of the IGBT module chip branch.

[0024] The isolated power supply unit has an input interface and multiple output interfaces, the input interface of the isolated power supply unit is used to connect to an external power supply, and the output interface of the isolated power supply unit is respectively connected to the drive circuit, the current sampling circuit and the peak monitoring circuit, wherein the isolated power supply unit outputs the +5c voltage value to the signal switching unit and the signal operation unit, and the isolated power supply unit also outputs two voltage values ​​of +5c and -5c to the peak monitoring circuit.

[0025] In this way, the isolation power supply unit is used to output a plurality of different voltage values ​​to meet the different requirements of the driving circuit, the current sampling circuit and the peak value monitoring circuit for the voltage value.

[0026] A multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, the driving circuit includes an IGBT gate driver Drv, a resistor Rg, a resistor Rd, a resistor Rr, a Schottky diode D3, a Schottky diode D4, an anti-static protection diode ESD, a capacitor C9, a resistor R6 and a resistor R7, the input end of the IGBT gate driver Drv is simultaneously connected to one end of the resistor R6 and one end of the capacitor C9, the other end of the resistor R6 is connected to the input control signal Si1 of the microprocessor, the other end of the capacitor C9 is grounded, the output end of the IGBT gate driver Drv is connected to one end of the resistor Rg, the other end of the resistor Rg is connected to the ground, and the output end of the IGBT gate driver Drv is connected to one end of the resistor Rg. The first end is connected to the cathode of the Schottky diode D3 and the anode of the Schottky diode D4 at the same time, the anode of the Schottky diode D3 is connected to one end of the resistor Rr, the other end of the resistor Rr is connected to the gate of the IGBT module, one end of the anti-static protection diode ESD, one end of the resistor Rd, one end of the resistor R7 and the input end of the current sampler at the same time, the other end of the resistor Rd is connected to the cathode of the Schottky diode D4, the other end of the anti-static protection diode ESD is connected to the other end of the resistor R7 and the emitter of the IGBT module at the same time, and the Schottky diode D4 and the resistor Rd form the current sampler.

[0027] In this way, when the input control signal Si1 is at a high level, the IGBT gate driver Drv outputs a gate current ig, which is the turn-on gate current igon. The current igon is injected into the IGBT module to turn it on. At this time, the voltage across the resistor Rd connected to the Schottky diode D4 is Rd*igon, and the voltage is further output to the emitter follower of the current sampling circuit as the output voltage of the current sampler; when the input control signal Si1 is at a low level, the IGBT gate driver Drv outputs a gate current ig in the opposite direction. At this time, the current is the turn-off gate current, which flows back to the IGBT gate driver Drv through the series circuit composed of the Schottky diode D3 and the resistor Rr, and the IGBT module, so that the IGBT module is turned off.

[0028] The emitter follower includes an operational amplifier OP1, a positive input terminal of the operational amplifier OP1 is connected to the output terminal of the current sampler, and a negative input terminal of the operational amplifier OP1 is connected to the output terminal of the operational amplifier OP1, and the output voltage of the operational amplifier OP1 will be further output to the signal switching unit of the current sampling circuit;

[0029] The signal switching unit includes a single-pole double-throw analog switch ST, the input end of the single-pole double-throw analog switch ST is connected to the input control signal Si2 of the microprocessor, and the single-pole double-throw analog switch ST further outputs the voltage signal output by the emitter follower to the signal operation unit when the input control signal Si2 is at a high level, and the single-pole double-throw analog switch ST outputs the ground signal to the signal operation unit when the input control signal Si2 is at a low level;

[0030] The signal operation unit includes an operational amplifier OP2, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, one end of the resistor R11 is connected to the output end of the signal switching unit, the other end of the resistor R11 is simultaneously connected to the positive input end of the operational amplifier OP2 and one end of the resistor R12, the other end of the resistor R12 is grounded, one end of the resistor R13 is connected to the output end of the operational amplifier OP2, the other end of the resistor R13 is simultaneously connected to one end of the resistor R14 and the reverse input end of the operational amplifier OP2, the other end of the resistor R14 is grounded, and the output end of the operational amplifier OP2 is also connected to the input end of the peak monitoring circuit;

[0031] The peak monitoring circuit includes a comparator Comp1, a common diode D10, a capacitor C10, an N-channel enhancement type MOSFET, a resistor R15 and a resistor R16, wherein the gate of the N-channel enhancement type MOSFET is connected to the input control signal Si1 of the microprocessor through an isolated gate driver and an inverter, the source of the N-channel enhancement type MOSFET is simultaneously connected to one end of the capacitor C10 and grounded, the other end of the capacitor C10 is simultaneously connected to the cathode of the Schottky diode D10, the drain of the N-channel enhancement type MOSFET and the reverse input end of the comparator Comp1, the anode of the common diode D10 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to the output end of the comparator Comp1, one end of the resistor R15 is connected to the output end of the signal operation unit, and the other end of the resistor R15 is connected to the positive input end of the comparator Comp1.

[0032] In this way, by setting the single-pole double-throw analog switch ST, the single-pole double-throw analog switch ST can realize the switching of two paths, so that when the input control signal Si2 is at a high level, the voltage signal output by the emitter follower is further output to the signal operation unit, and when the input control signal Si2 is at a low level, the ground terminal signal is output to the signal operation unit; when the input control signal Si2 is at a high level so that the voltage signal output by the emitter follower is further output to the signal operation unit, the signal operation unit uses the operational amplifier OP2, the resistor R11, the resistor R12, the resistor R13 and the resistor R14 to perform operation processing on the voltage signal and further output it to the peak monitoring circuit. The peak monitoring circuit uses the comparator Comp1, the ordinary diode D10, the capacitor C10, the resistor R15 and the resistor R16 to keep the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit, and the voltage U on the capacitor C10 C10 Changes with the change of the peak current injected into the gate of the IGBT module; when the input control signal Si2 maintains k switching cycles, the voltage U on the capacitor C10 C10 Accumulate the changes and collect the voltage signal U containing the gate peak current information C10 , by judging the voltage U under the current operation of the IGBT module C10 Voltage U under healthy module operation C10 After the sampling process is completed, the input control signal Si2 is set to a low level, and the charge on the capacitor C10 will be released through the N-channel enhancement MOSFET, thus preparing for the next state monitoring process.

[0033] The present invention provides a multi-chip IGBT module chip branch defect monitoring method and circuit based on gate peak current, and the technical effects are as follows:

[0034] 1: The present invention has the potential for real-time online monitoring. At the same time, the monitoring circuit has a high degree of integration, and the monitoring method is easy to implement. At the same time, it can convert the short-pulse gate peak current information as a transient quantity into a smooth DC signal as a steady-state quantity, reduce the sampling frequency, reduce costs, and measure the device chip branch state without disassembling the device.

[0035] 2: The present invention provides a multi-chip IGBT module chip branch defect monitoring method and circuit based on gate peak current, so that the chip branch status of the IGBT module can be obtained without disassembling it; the monitoring method is easy to measure, and can convert the short-pulse gate peak current information as a transient quantity into a smooth DC signal as a steady-state quantity, while reducing the sampling frequency and cost, and has the potential for real-time online monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a structural block diagram of a multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current.

[0037] Figure 2 The present invention is a circuit schematic diagram of a driving circuit in a chip branch defect monitoring circuit of a multi-chip IGBT module based on gate peak current.

[0038] Figure 3 The present invention is a circuit schematic diagram of a current sampling circuit in a chip branch defect monitoring circuit of a multi-chip IGBT module based on gate peak current.

[0039] Figure 4 The present invention is a circuit schematic diagram of a peak monitoring circuit in a chip branch defect monitoring circuit of a multi-chip IGBT module based on gate peak current.

[0040] Figure 5 The circuit schematic diagram of the multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current of the present invention.

[0041] Explanation of the reference numerals: current sampler 1 , emitter follower 2 , signal switching unit 3 , signal operation unit 4 , peak value monitoring circuit 5 , driving circuit 6 . DETAILED DESCRIPTION

[0042] A chip branch defect monitoring method for a multi-chip IGBT module based on gate peak current. Since the gate peak current of the IGBT module during the switching process will be affected by the change of its internal parameters due to the aging of the IGBT module, the health status of the current IGBT module can be evaluated by monitoring the gate peak current of the IGBT module during the switching process.

[0043] Since the IGBT module needs to withstand the thermal mechanical stress generated by the power cycle, it will age and its internal parameters or structure will change, which will gradually reduce the safety and reliability of the IGBT module. At the same time, the gate peak current of the IGBT module during the switching process will also change, which provides conditions for the health status monitoring of the IGBT module. This solution collects and processes the gate peak current during the switching process of the IGBT module, and can be easily monitored without disassembling the IGBT module, ensuring that the IGBT module works under normal conditions while accurately evaluating its health status, thereby improving the safety and reliability of the module and system.

[0044] A multi-chip IGBT module chip branch defect monitoring method based on gate peak current takes the IGBT module gate peak current as the monitoring object and evaluates the current IGBT module chip branch defect situation by continuously comparing the changes in gate peak current obtained under multiple switching cycles.

[0045] A multi-chip IGBT module chip branch defect monitoring method based on gate peak current. Since the chip branch defects of the IGBT module will change the internal parameters of the IGBT module, causing the gate peak current of the IGBT module to change during the turn-on and turn-off processes, the gate peak current of the IGBT module during the turn-on process can be monitored to monitor the chip branch defects of the IGBT module.

[0046] like Figure 1 As shown, a monitoring circuit for implementing the above-mentioned multi-chip IGBT module chip branch defect monitoring method based on gate peak current includes:

[0047] A drive circuit for controlling the on and off of the IGBT module;

[0048] The current sampling circuit is used to obtain the gate current of the IGBT module during the turn-on process, and convert the obtained gate current into a synchronously changing voltage signal and output it to the peak monitoring circuit;

[0049] The peak monitoring circuit is used to monitor the gate peak current.

[0050] The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current also includes a microprocessor for generating an input control signal Si2. The current sampling circuit receives the input control signal Si2, and monitors the gate current obtained by the current sampler when the input control signal Si2 is at a high level to obtain gate peak current information. The circuit is reset when the input control signal Si2 is at a low level. When the input control signal Si2 is maintained at a high level in each switching cycle, the peak detection circuit can also compare the gate peak current.

[0051] In this way, the input control signal Si2 is used to control whether to collect the gate current of the IGBT module, so as to monitor the defect status of the IGBT module chip branch according to the monitoring needs. At the same time, by keeping the input control signal Si2 at a high level in multiple switching cycles, the current collection circuit collects the gate peak current of multiple switching cycles, and compares the gate peak current information, so as to achieve the purpose of monitoring the defect status of the IGBT module chip branch.

[0052] A multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, wherein the microprocessor is also used to generate an input control signal Si1, which is used to control the normal opening and closing of the IGBT module through a driver, and controls the IGBT module to be turned on when the input control signal Si1 is at a high level, and controls the IGBT module to be turned off when the input control signal Si1 is at a low level.

[0053] like Figure 1 As shown, the multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current also includes:

[0054] An isolated power supply circuit, whose output ends are respectively connected to the drive circuit, the current sampling circuit and the peak monitoring circuit, and is used to supply power to the drive circuit, the current sampling circuit and the peak monitoring circuit;

[0055] The current sampling circuit includes a current sampler 1, an emitter follower 2, a signal switching unit 3 and a signal operation unit 4. The emitter follower 2 is connected to the output end of the current sampler 1 and is used to output the voltage signal output by the current sampler 1 to the signal switching unit 3; the signal switching unit 3 is used to receive the voltage signal or the ground signal output by the emitter follower 2, and output the voltage signal to the signal operation unit 4 when receiving the voltage signal; the signal operation unit 4 is used to receive the voltage signal output by the signal switching unit 3, and output the voltage signal to the peak monitoring circuit 5 after performing operation processing on the voltage signal.

[0056] Thus, when the monitoring circuit of the present invention is used, the driving circuit controls the IGBT module to be turned on. At this time, the current sampler 1 outputs a voltage signal that changes synchronously with the gate current to the emitter follower 2; the emitter follower 2 receives the voltage signal output by the current sampler 1, and outputs the voltage signal to the signal switching unit 3, the signal switching unit 3 outputs the received voltage signal or the ground signal to the signal operation unit 4, the signal operation unit 4 performs operation processing on the received voltage signal and outputs it to the peak monitoring circuit 5, the peak monitoring circuit 5 receives the voltage signal output by the signal operation unit 4, and keeps the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit 5; since the voltage signal output by the current sampler 1 changes synchronously with the gate peak current, and the gate peak current contains the information of the IGBT module chip branch defect, the voltage on the capacitor C10 finally also contains the information of the IGBT module chip branch defect, so the voltage U on the capacitor C10 is used to detect the gate peak current information. C10 It can be used to characterize IGBT module chip branch defects.

[0057] The monitoring circuit of the present invention can not only ensure the normal operation of the IGBT module, but also perform monitoring without disassembling the IGBT module, and has the potential for real-time online monitoring. At the same time, the monitoring circuit has high integration, and the monitoring method is easy to implement. At the same time, it can convert the short-pulse gate peak current information as a transient quantity into a smooth DC signal as a steady-state quantity, thereby reducing the sampling frequency, reducing the cost, and accurately evaluating the aging state of the IGBT module, thereby improving the safety and reliability of the IGBT module and the system having the IGBT module, and has practical application value.

[0058] In the multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, the signal switching unit 3 in the current sampling circuit receives the input control signal Si2 issued by the microprocessor, and can output a voltage signal that changes synchronously with the gate current to the signal operation unit 4 when the input control signal Si2 is at a high level. The voltage signal is output to the peak monitoring circuit 5 via the signal operation unit 4. The peak monitoring circuit 5 compares the voltage signal with the voltage across the capacitor C10 to perform a state monitoring process; and the signal switching unit 3 in the current sampling circuit resets the charge of the capacitor C10 when the input control signal Si2 is at a low level, and the state monitoring ends.

[0059] Thus, when monitoring is performed, the microprocessor sends an input control signal Si2 at a high level. At the same time, when the input control signal Si1 sent by the microprocessor is also at a high level, the drive circuit 6 will control the IGBT module to turn on. The signal switching unit 3 in the current sampling circuit further outputs the received voltage signal output by the emitter follower 2 to the signal operation unit 4, and the peak monitoring circuit 5 keeps the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit 5; the voltage U on the capacitor C10 is C10 The voltage U on capacitor C10 is collected. C10 To characterize the defect status of the IGBT module chip branch.

[0060] The isolated power supply unit has an input interface and multiple output interfaces. The input interface of the isolated power supply unit is used to connect to an external power supply, and the output interface of the isolated power supply unit is respectively connected to the driving circuit 6, the current sampling circuit and the peak monitoring circuit 5. The isolated power supply unit outputs the +5c voltage value to the signal switching unit 3 and the signal operation unit 4. The isolated power supply unit also outputs the two voltage values ​​of +5c and -5c to the peak monitoring circuit 5.

[0061] In this way, the isolated power supply unit is used to output a plurality of different voltage values ​​to meet the different requirements of the driving circuit 6 , the current sampling circuit and the peak value monitoring circuit 5 on the voltage values.

[0062] like Figure 2 As shown, a multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, the drive circuit 6 includes an IGBT gate driver Drv, a resistor Rg, a resistor Rd, a resistor Rr, a Schottky diode D3, a Schottky diode D4, an anti-static protection diode ESD, a capacitor C9, a resistor R6 and a resistor R7, the input end of the IGBT gate driver Drv is simultaneously connected to one end of the resistor R6 and one end of the capacitor C9, the other end of the resistor R6 is connected to the input control signal Si1 of the microprocessor, the other end of the capacitor C9 is grounded, and the output end of the IGBT gate driver Drv is connected to one end of the resistor Rg. The anode of the Schottky diode D3 is connected to one end of the resistor Rr, the other end of the resistor Rr is connected to the gate of the IGBT module, one end of the anti-static protection diode ESD, one end of the resistor Rd, one end of the resistor R7 and the input end of the current sampler, the other end of the resistor Rd is connected to the cathode of the Schottky diode D4, the other end of the anti-static protection diode ESD is connected to the other end of the resistor R7 and the emitter of the IGBT module, and the Schottky diode D4 and the resistor Rd form a current sampler 1.

[0063] In this way, when the input control signal Si1 is at a high level, the IGBT gate driver Drv outputs a gate current ig, which is the turn-on gate current igon. The current igon is injected into the IGBT module to turn it on. At this time, the voltage across the resistor Rd connected to the Schottky diode D4 is Rd*igon, and the voltage is further output to the emitter follower 2 of the current sampling circuit as the output voltage of the current sampler 1; when the input control signal Si1 is at a low level, the IGBT gate driver Drv outputs a gate current ig in the opposite direction. At this time, the current is the turn-off gate current, which flows back to the IGBT gate driver Drv through the series circuit composed of the Schottky diode D3 and the resistor Rr, and the IGBT module, so that the IGBT module is turned off.

[0064] like Figure 3 As shown, the emitter follower 2 includes an operational amplifier OP1, the positive input terminal of the operational amplifier OP1 is connected to the output terminal of the current sampler 1, and the reverse input terminal of the operational amplifier OP1 is connected to the output terminal of the operational amplifier OP1, and the output voltage of the operational amplifier OP1 will be further output to the signal switching unit 3 of the current sampling circuit;

[0065] The signal switching unit 3 includes a single-pole double-throw analog switch ST, the input end of the single-pole double-throw analog switch ST is connected to the input control signal Si2 of the microprocessor, and the single-pole double-throw analog switch ST further outputs the voltage signal output by the emitter follower 2 to the signal operation unit 4 when the input control signal Si2 is at a high level, and the single-pole double-throw analog switch ST outputs the ground signal to the signal operation unit 4 when the input control signal Si2 is at a low level;

[0066] The signal operation unit 4 includes an operational amplifier OP2, a resistor R11, a resistor R12, a resistor R13 and a resistor R14, one end of the resistor R11 is connected to the output end of the signal switching unit 3, the other end of the resistor R11 is simultaneously connected to the positive input end of the operational amplifier OP2 and one end of the resistor R12, the other end of the resistor R12 is grounded, one end of the resistor R13 is connected to the output end of the operational amplifier OP2, the other end of the resistor R13 is simultaneously connected to one end of the resistor R14 and the reverse input end of the operational amplifier OP2, the other end of the resistor R14 is grounded, and the output end of the operational amplifier OP2 is also connected to the input end of the peak monitoring circuit 5;

[0067] like Figure 4As shown, the peak monitoring circuit 5 includes a comparator Comp1, a common diode D10, a capacitor C10, an N-channel enhancement type MOSFET, a resistor R15 and a resistor R16. The gate of the N-channel enhancement type MOSFET is connected to the input control signal Si1 of the microprocessor through an isolated gate driver and an inverter. The source of the N-channel enhancement type MOSFET is simultaneously connected to one end of the capacitor C10 and grounded. The other end of the capacitor C10 is simultaneously connected to the cathode of the Schottky diode D10, the drain of the N-channel enhancement type MOSFET and the reverse input end of the comparator Comp1. The anode of the common diode D10 is connected to one end of the resistor R16. The other end of the resistor R16 is connected to the output end of the comparator Comp1. One end of the resistor R15 is connected to the output end of the signal operation unit 4. The other end of the resistor R15 is connected to the positive input end of the comparator Comp1.

[0068] In this way, by setting the single-pole double-throw analog switch ST, the single-pole double-throw analog switch ST can realize the switching of two paths, so that when the input control signal Si2 is at a high level, the voltage signal output by the emitter follower 2 is further output to the signal operation unit 4, and when the input control signal Si2 is at a low level, the ground terminal signal is output to the signal operation unit 4; when the input control signal Si2 is at a high level so that the voltage signal output by the emitter follower 2 is further output to the signal operation unit 4, the signal operation unit 4 uses the operational amplifier OP2, the resistor R11, the resistor R12, the resistor R13 and the resistor R14 to perform operation processing on the voltage signal and further output it to the peak monitoring circuit 5, the peak monitoring circuit 5 uses the comparator Comp1, the ordinary diode D10, the capacitor C10, the resistor R15 and the resistor R16 to keep the voltage signal containing the gate peak current information on the capacitor C10 in the peak monitoring circuit 5, and the voltage U on the capacitor C10 C10 Changes with the change of the peak current injected into the gate of the IGBT module; when the input control signal Si2 maintains k switching cycles, the voltage U on the capacitor C10 C10 Accumulate the changes and collect the voltage signal U containing the gate peak current information C10 , by judging the voltage U under the current operation of the IGBT module C10 Voltage U under healthy module operation C10 After the sampling process is completed, the input control signal Si2 is set to a low level, and the charge on the capacitor C10 will be released through the N-channel enhancement MOSFET, thus preparing for the next state monitoring process.

[0069] The multi-chip IGBT module chip branch defect monitoring method and circuit based on gate peak current of the present invention have the potential for real-time online monitoring. At the same time, the monitoring circuit has high integration, and the monitoring method is easy to implement. At the same time, it can convert short-pulse gate peak current information as a transient quantity into a smooth DC signal as a steady-state quantity, reduce the sampling frequency, reduce costs, and measure the chip branch status of the device without disassembling the device.

Claims

1. A method for monitoring chip branch defects of a multi-chip IGBT module based on gate peak current, characterized in that: Taking the gate peak current of the IGBT module as the monitoring object, the current IGBT module chip branch defect situation is evaluated by continuously comparing the changes in the gate peak current obtained under multiple switching cycles.

2. A method for monitoring chip branch defects of a multi-chip IGBT module based on gate peak current, characterized in that: The branch defects of the IGBT module chip will change the internal parameters of the IGBT module, causing the gate peak current of the IGBT module to change during the turn-on and turn-off processes. Therefore, the branch defects of the IGBT module chip can be monitored by monitoring the gate peak current of the IGBT module during the turn-on process.

3. A multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current, characterized in that include: A drive circuit, the drive circuit is connected to the IGBT module and is used to control the on and off of the IGBT module; The current sampling circuit is connected to the IGBT module and the peak monitoring circuit respectively. The current sampling circuit is used to obtain the gate current of the IGBT module during the opening process, and convert the obtained gate current into a synchronously changing voltage signal and then output it to the peak monitoring circuit; The peak monitoring circuit is used to monitor the gate peak current.

4. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The circuit also includes: a microprocessor, which is respectively connected to the current sampling circuit, the driving circuit, and the peak value monitoring circuit; The microprocessor generates an input control signal Si2, and the current sampling circuit receives the input control signal Si2. When the input control signal Si2 is at a high level, the current sampling circuit monitors the gate current obtained by the current sampling circuit to obtain the gate peak current information. When the input control signal Si2 is at a low level, the microprocessor resets. The input control signal Si2 is maintained at a high level in each switching cycle. The peak monitoring circuit can also compare the gate peak current. The microprocessor generates an input control signal Si1, which is used to control the normal opening and closing of the IGBT module through the drive circuit. When the input control signal Si1 is at a high level, the IGBT module is controlled to be turned on, and when the input control signal Si1 is at a low level, the IGBT module is controlled to be turned off.

5. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The circuit also includes: an isolation power supply circuit, which is respectively connected to the drive circuit, the current sampling circuit, and the peak value monitoring circuit, and is used to supply power to the drive circuit, the current sampling circuit, and the peak value monitoring circuit.

6. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 5, characterized in that: The current sampling circuit comprises: a current sampler, an emitter follower, a signal switching unit and a signal operation unit; The emitter follower is connected to the output end of the current sampler and is used to output the voltage signal output by the current sampler to the signal switching unit; the signal switching unit is used to receive the voltage signal or the ground signal output by the current sampler, and output the voltage signal to the signal operation unit when receiving the voltage signal; the signal operation unit is used to receive the voltage signal output by the signal switching unit, and output the voltage signal to the peak monitoring circuit after operation processing.

7. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The signal switching unit in the current sampling circuit receives the input control signal Si2 sent by the microprocessor, and can output a voltage signal that changes synchronously with the gate current to the signal operation unit when the input control signal Si2 is at a high level. The voltage signal is output to the peak monitoring circuit via the signal operation unit. The peak monitoring circuit compares the voltage signal with the voltage across the capacitor C10 to perform a state monitoring process; and the signal switching unit in the current sampling circuit resets the charge of the capacitor C10 when the input control signal Si2 is at a low level, and the state monitoring ends.

8. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The driving circuit includes an IGBT gate driver Drv, a resistor Rg, a resistor Rr, a Schottky diode D3, an anti-static protection diode ESD, a capacitor C9, a resistor R6 and a resistor R7; The input end of the IGBT gate driver Drv is respectively connected to one end of the resistor R6 and one end of the capacitor C9, the other end of the resistor R6 is connected to the input control signal Si1 of the microprocessor, and the other end of the capacitor C9 is grounded; the output end of the IGBT gate driver Drv is connected to one end of the resistor Rg, the other end of the resistor Rg is respectively connected to the cathode of the Schottky diode D3 and the anode of the Schottky diode D4, and the anode of the Schottky diode D3 is connected to one end of the resistor Rr; the other end of the resistor Rr is respectively connected to the gate of the IGBT module, one end of the anti-static protection diode ESD, one end of the resistor Rd, one end of the resistor R7, and the input end of the current sampler; the other end of the resistor Rd is connected to the cathode of the Schottky diode D4, and the other end of the anti-static protection diode ESD is respectively connected to the other end of the resistor R7 and the emitter of the IGBT module.

9. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The signal switching unit includes a single-pole double-throw analog switch ST, the input end of the single-pole double-throw analog switch ST is connected to the input control signal Si2 of the microprocessor, and when the input control signal Si2 is at a high level, the single-pole double-throw analog switch ST further outputs the voltage signal output by the emitter follower 2 to the signal switching unit, and when the input control signal Si2 is at a low level, the single-pole double-throw analog switch ST outputs the ground signal to the signal switching unit.

10. The multi-chip IGBT module chip branch defect monitoring circuit based on gate peak current according to claim 3, characterized in that: The peak monitoring circuit includes a comparator Comp1, a common diode D10, a capacitor C10, an N-channel enhancement type MOSFET, a resistor R15 and a resistor R16; the gate of the N-channel enhancement type MOSFET is connected to the input control signal Si1 of the microprocessor through an isolated gate driver and an inverter, the source of the N-channel enhancement type MOSFET is simultaneously connected to one end of the capacitor C10 and grounded, the other end of the capacitor C10 is simultaneously connected to the cathode of the Schottky diode D10, the drain of the N-channel enhancement type MOSFET and the reverse input end of the comparator Comp1, the anode of the common diode D10 is connected to one end of the resistor R16, the other end of the resistor R16 is connected to the output end of the comparator Comp1, one end of the resistor R15 is connected to the output end of the signal operation unit, and the other end of the resistor R15 is connected to the positive input end of the comparator Comp1.

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