SiC mosfet module multi-scale protection circuit

Abstract

The application discloses a SiC MOSFET module multi-scale protection circuit, comprising: a current sampling unit module, a voltage sampling unit module, a short-circuit detection unit module, an overload detection unit module based on energy accumulation, and a protection judgment unit module. The short-circuit protection function and the overload protection function based on energy accumulation are integrated together, so that the SiC MOSFET module can be quickly protected when a short circuit occurs, and the protection function can be provided when an overload fault with a relatively low current level occurs, and heat accumulation generated for a long time exceeds the heat limit of a device to cause damage of the device.

Description

Technical Field

[0001] This invention belongs to the field of short-circuit protection technology and relates to a multi-scale protection circuit for SiC MOSFET modules. Background Technology

[0002] In recent years, silicon carbide (SiC) devices, as third-generation wide-bandgap power semiconductor devices, have shown great potential in high-voltage, high-temperature, high-power, and high-frequency applications due to their excellent material properties. SiC MOSFETs are widely used in smart grids, smart homes, transportation electrification, electric vehicles and hybrid vehicles, as well as other emerging industrial and medical fields. For SiC MOSFETs, due to the high cost of power modules and safety considerations, protection circuit design has always been crucial. Compared to Si devices, SiC MOSFETs have shorter short-circuit withstand times and weaker withstand capabilities due to their smaller chip area and higher current density, and they degrade rapidly under short-circuit conditions. Especially for high-current SiC MOSFET power modules, the short-circuit safe operating area (SOA) is generally limited to a few microseconds, and its robustness is far lower than that of Si IGBTs. For large-scale applications, further improvements in equipment reliability are needed, and protection circuits also need to be reconsidered to adapt to device characteristics and effectively protect SiC MOSFETs. Currently, the main methods for short-circuit detection of SiC MOSFETs include: desaturation detection, parasitic inductance detection, shunt detection, gate voltage detection, and Rogowski coil-based current detection, among others. However, none of the existing methods take into account the short-circuit characteristics and failure mechanisms of SiC MOSFETs. They can only achieve a single detection function, and their accuracy is easily affected by temperature or external factors. Summary of the Invention

[0003] The purpose of this invention is to provide a multi-scale protection circuit for SiC MOSFET modules, which integrates short-circuit protection and energy accumulation-based overload protection, thereby improving the operating life of SiC MOSFET modules.

[0004] The technical solution adopted in this invention is a multi-scale protection circuit for a SiC MOSFET module, including: a current sampling unit module, a voltage sampling unit module, a short-circuit detection unit module, an overload detection unit module based on energy accumulation, and a protection judgment unit module; The current sampling unit module is used to sample current signals; the voltage sampling unit module is used to sample voltage signals; the short-circuit detection unit module is used to detect whether a short-circuit fault has occurred in the SiC MOSFET module; the energy accumulation-based overload detection unit module is used to detect whether an overload fault has occurred in the SiC MOSFET module; and the protection judgment unit module is used to perform an OR logic operation on the output signals of the short-circuit detection unit module and the energy accumulation-based overload detection unit module to output a total fault signal.

[0005] The invention is further characterized in that, The current sampling unit module includes an inductor. L s ,capacitance C f ,resistance R f , C f and R f After being connected in series and in L s At both ends, the current sampling unit module measures the voltage across the inductor between the power source terminal and the Kelvin source terminal of the SiC MOSFET module, and then uses an integrating circuit to restore the voltage signal into a signal proportional to the module current signal.

[0006] The voltage sampling unit module includes resistors R 1 and resistance R 2, R 1 and R 2 is connected in series between the drain of the SiC MOSFET module and ground. The voltage sampling unit module measures the voltage between the source and drain of the SiC MOSFET module through a resistor voltage divider and transmits the voltage signal to the energy accumulation-based overload detection unit module.

[0007] The short-circuit detection unit module includes comparator A2, one input of which is connected to a resistor via a wire. R f With capacitor C f Between these steps, the short-circuit detection unit module compares the sampling signal from the current sampling unit module with the set reference threshold to determine whether a short-circuit fault has occurred in the SiC MOSFET.

[0008] If the sampling signal of the current sampling unit module is greater than the corresponding reference voltage, then the SiC MOSFET module has experienced a short circuit fault, and the output signal of the short circuit detection unit module flips to a high level; if the sampling signal of the current sampling unit module is less than or equal to the corresponding reference voltage, then the SiC MOSFET module has not experienced a short circuit fault.

[0009] The energy accumulation-based overload detection unit module includes MOSFET M1, MOSFET M2, MOSFET M3, and a capacitor. What, Comparator A1 and M1 have their gates connected to the output signal of the voltage sampling unit and their sources connected to the output signal of the current sampling unit. The current generated on M1 is copied to M3 through M2. The capacitor... What Connected to the non-inverting input of comparator A1, the energy accumulation-based overload detection unit module uses comparator A1 to simultaneously perform energy detection on the sampling signals from the current sampling unit module and the voltage sampling unit module, compares the detected signals with a set reference threshold, and determines whether the SiCMOSFET has experienced an overload fault.

[0010] If the sampling signal of the energy accumulation-based overload detection unit module is greater than the corresponding reference voltage, the SiCMOSFET module has experienced an overload fault, and the output signal of the energy accumulation-based overload detection unit module flips to a high level; if the sampling signal of the energy accumulation-based overload detection unit module is less than or equal to the corresponding reference voltage, the SiCMOSFET module has not experienced an overload fault.

[0011] The protection judgment unit module includes an OR gate and a latch. The two inputs of the OR gate are connected to the outputs of comparators A1 and A2, respectively, and the output of the OR gate is connected to the input of the latch. The protection judgment unit module is used to output a total fault signal by performing an OR logic operation on the output signals of the short circuit detection unit module and the energy accumulation-based overload detection unit module. This fault signal is then sent to the main drive circuit after passing through the latch to control the turn-on and turn-off of the SiC MOSFET.

[0012] The beneficial effects of this invention are: This invention presents a multi-scale protection circuit for SiC MOSFET modules, integrating short-circuit protection and energy-accumulation-based overload protection. It provides rapid protection against short circuits and also offers protection against overload faults with relatively low current levels, where prolonged heat accumulation exceeds the device's thermal limit and causes damage. This solves the problems of existing protection circuits having limited detection capabilities and failing to address failure mechanisms, significantly improving the lifespan of SiC MOSFET modules and increasing system reliability. Furthermore, the protection circuit can be customized with different reference thresholds to meet the diverse needs of different users, achieving more comprehensive, effective, and multi-scale protection. Attached Figure Description

[0013] Figure 1 This is a circuit structure diagram of the multi-scale protection circuit for the SiC MOSFET module of the present invention.

[0014] In the diagram, 1. Current sampling unit module, 2. Voltage sampling unit module, 3. Short circuit detection unit module, 4. Overload detection unit module based on energy accumulation, and 5. Protection judgment unit module. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] The present invention provides a multi-scale protection circuit for SiC MOSFET modules, such as... Figure 1 As shown, it includes: current sampling unit module 1, voltage sampling unit module 2, short circuit detection unit module 3, overload detection unit module 4 based on energy accumulation, and protection judgment unit module 5.

[0017] Current sampling unit module 1 is used to sample current signals; current sampling unit module 1 includes an inductor. L s ,capacitance C f ,resistance R f , C f and R f After being connected in series and in L s At both ends, the current sampling unit module 1 measures the voltage across the inductor between the power source terminal and the Kelvin source terminal of the SiC MOSFET module, and then uses an integrating circuit to restore the voltage signal into a signal proportional to the module current signal.

[0018] Voltage sampling unit module 2 is used to sample voltage signals; voltage sampling unit module 2 includes resistors. R 1 and resistance R 2, R 1 and R 2 is connected in series between the drain of the SiC MOSFET module and ground. The voltage sampling unit module 2 measures the voltage between the source and drain of the SiC MOSFET module through resistor voltage division and transmits the voltage signal to the energy accumulation-based overload detection unit module 4.

[0019] Short-circuit detection unit module 3 is used to detect whether a short-circuit fault has occurred in the SiC MOSFET module; short-circuit detection unit module 3 includes comparator A2, one input terminal of comparator A2 is connected to a resistor via a wire. R f With capacitor C f Between these steps, the short-circuit detection unit module 3 compares the sampling signal from the current sampling unit module 1 with the set reference threshold to determine whether a short-circuit fault has occurred in the SiCMOSFET.

[0020] If the sampling signal of the current sampling unit module 1 is greater than the corresponding reference voltage, then the SiC MOSFET module has experienced a short circuit fault, and the output signal of the short circuit detection unit module 3 flips to a high level; if the sampling signal of the current sampling unit module 1 is less than or equal to the corresponding reference voltage, then the SiC MOSFET module has not experienced a short circuit fault.

[0021] The energy accumulation-based overload detection unit module 4 is used to detect whether an overload fault has occurred in the SiC MOSFET module; the energy accumulation-based overload detection unit module 4 includes MOSFET M1, MOSFET M2, MOSFET M3, and capacitor. What, Comparator A1 and M1 have their gates connected to the output signal of the voltage sampling unit and their sources connected to the output signal of the current sampling unit. The current generated on M1 is copied to M3 through M2. The capacitor... What Connected to the non-inverting input of comparator A1, the overload detection unit module 4 based on energy accumulation uses comparator A1 to simultaneously perform energy detection on the sampling signals of the current sampling unit module 1 and the voltage sampling unit module 2, compares the detected signals with a set reference threshold, and determines whether the SiCMOSFET has experienced an overload fault.

[0022] If the sampling signal of the energy accumulation-based overload detection unit module 4 is greater than the corresponding reference voltage, then the SiCMOSFET module has experienced an overload fault, and the output signal of the energy accumulation-based overload detection unit module 4 flips to a high level; if the sampling signal of the energy accumulation-based overload detection unit module 4 is less than or equal to the corresponding reference voltage, then the SiCMOSFET module has not experienced an overload fault.

[0023] The protection judgment unit module 5 includes an OR gate and a latch. The two inputs of the OR gate are connected to the outputs of comparators A1 and A2, respectively, and the output of the OR gate is connected to the input of the latch. The protection judgment unit module 5 is used to output a total fault signal by performing an OR logic operation on the output signals of the short circuit detection unit module 3 and the energy accumulation-based overload detection unit module 4. After passing through the latch, the fault signal is sent to the main drive circuit to control the turn-on and turn-off of the SiC MOSFET.

[0024] As can be seen from the above, the multi-scale protection circuit for SiC MOSFET modules of this invention, starting from the failure mechanism of SiC MOSFETs, proposes a multi-scale protection circuit for SiC MOSFET modules that integrates short-circuit protection and energy accumulation-based overload protection. Two protection detection unit modules simultaneously perform fault judgment, and the judgment signals output by both are logically processed to finally output a total fault signal. Regardless of the type of fault, the fault signal will be detected and triggered, thereby improving the working life of the SiC MOSFET module and increasing the reliability of the system.

Claims

1. A multi-scale protection circuit for a SiC MOSFET module, characterized in that, include: Current sampling unit module (1), voltage sampling unit module (2), short circuit detection unit module (3), overload detection unit module based on energy accumulation (4), protection judgment unit module (5); The current sampling unit module (1) is used to sample current signals; the voltage sampling unit module (2) is used to sample voltage signals; the short circuit detection unit module (3) is used to detect whether a short circuit fault has occurred in the SiC MOSFET module; the energy accumulation-based overload detection unit module (4) is used to detect whether an overload fault has occurred in the SiC MOSFET module; the protection judgment unit module (5) is used to perform an OR logic operation on the output signals of the short circuit detection unit module (3) and the energy accumulation-based overload detection unit module (4) to output a total fault signal; The current sampling unit module (1) includes an inductor. L s ,capacitance C f ,resistance R f , C f and R f After being connected in series and in L s At both ends, the current sampling unit module (1) measures the voltage on the inductor between the power source terminal and the Kelvin source terminal of the SiC MOSFET module, and then restores the voltage signal to a signal proportional to the module current signal through an integration circuit; The voltage sampling unit module (2) includes resistors R 1 and resistance R 2, R 1 and R 2 is connected in series between the drain of the SiC MOSFET module and ground. The voltage sampling unit module (2) measures the voltage between the source and drain of the SiC MOSFET module through resistor voltage division and transmits the voltage signal to the energy accumulation-based overload detection unit module (4). The short-circuit detection unit module (3) includes a comparator A2, one input terminal of which is connected to a resistor via a wire. R f With capacitor C f Between, the short-circuit detection unit module (3) compares the sampling signal of the current sampling unit module (1) with the set reference threshold to determine whether the SiC MOSFET has a short-circuit fault; The energy accumulation-based overload detection unit module (4) includes MOSFET M1, MOSFET M2, MOSFET M3, and capacitor. Ce、 Comparator A1 and M1 have their gates connected to the output signal of the voltage sampling unit and their sources connected to the output signal of the current sampling unit. The current generated on M1 is copied to M3 through M2. The capacitor... Ce Connected to the non-inverting input of comparator A1, the energy accumulation-based overload detection unit module (4) performs energy detection by comparator A1 simultaneously by sampling signals from current sampling unit module (1) and voltage sampling unit module (2), compares the detection signal with a set reference threshold, and determines whether the SiCMOSFET has an overload fault.

2. The multi-scale protection circuit for the SiC MOSFET module according to claim 1, characterized in that, If the sampling signal of the current sampling unit module (1) is greater than the corresponding reference voltage, then the SiC MOSFET module has a short circuit fault, and the output signal of the short circuit detection unit module (3) flips to a high level; if the sampling signal of the current sampling unit module (1) is less than or equal to the corresponding reference voltage, then the SiC MOSFET module has not a short circuit fault.

3. The multi-scale protection circuit for the SiC MOSFET module according to claim 1, characterized in that, If the sampling signal of the energy accumulation-based overload detection unit module (4) is greater than the corresponding reference voltage, then the SiC MOSFET module has experienced an overload fault, and the output signal of the energy accumulation-based overload detection unit module (4) flips to a high level; if the sampling signal of the energy accumulation-based overload detection unit module (4) is less than or equal to the corresponding reference voltage, then the SiC MOSFET module has not experienced an overload fault.

4. The multi-scale protection circuit for the SiC MOSFET module according to claim 1, characterized in that, The protection judgment unit module (5) includes an OR gate and a latch. The two input terminals of the OR gate are respectively connected to the output terminals of comparators A1 and A2, and the output terminal of the OR gate is connected to the input terminal of the latch. The protection judgment unit module (5) is used to output a total fault signal by performing an OR logic operation on the output signals of the short circuit detection unit module (3) and the energy accumulation-based overload detection unit module (4). The fault signal is then sent to the main drive circuit after passing through the latch to control the turn-on and turn-off of the SiC MOSFET.

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