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CN-122026707-A - SiC module overvoltage clamping grid driver, control method thereof and power conversion device

CN122026707ACN 122026707 ACN122026707 ACN 122026707ACN-122026707-A

Abstract

The invention discloses an over-voltage clamping grid driver of a SiC module, a control method thereof and a power conversion device, which comprises the SiC module, a drain clamping unit, a grid amplifier and a logic control unit, wherein the drain clamping unit is electrically connected with the SiC module and is used for clamping an over-voltage peak of a drain and a source of the SiC module at a safety threshold V dth and outputting an over-voltage fault signal V fal , the grid amplifier is electrically connected with the SiC module and is used for switching on and off the SiC module, when an over-voltage fault happens, the clamping current is blocked to split the grid amplifier, and the logic control unit is electrically connected with the drain clamping unit and the grid amplifier and is used for controlling logic of the grid amplifier according to the over-voltage fault signal V fal and a switching signal V PWM . The invention has the advantages of simple structure and rapid dynamic response, can effectively enhance the overvoltage suppression capability of the SiC module under the off working condition, and provides reliable guarantee for the stable operation of the SiC module.

Inventors

  • TAN GUOJUN
  • Qiu Qiaolong
  • ZHANG JINGWEI
  • YANG BO

Assignees

  • 江苏国传电气有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (11)

  1. 1. The SiC module over-voltage clamping grid driver is characterized in that the SiC module is integrated with at least one SiC power chip and a packaging parasitic structure, and comprises: The drain clamping unit is connected with a drain terminal of the SiC module and used for monitoring the drain-source voltage of the SiC module, clamping an overvoltage peak of a drain-source electrode of the SiC module at a safety threshold V dth and synchronously outputting an overvoltage fault signal V fal ; The grid amplifier is electrically connected with a grid terminal of the SiC module and is used for receiving a switching signal V PWM to control on and off control of the SiC module, and blocking clamping current to shunt to the grid amplifier through linkage control of the logic control unit when an off overvoltage fault occurs; And the logic control unit is respectively and electrically connected with the drain clamping unit and the gate amplifier and is used for performing turn-off control on the gate amplifier according to the overvoltage fault signal V fal and the switch signal V PWM to ensure that clamping currents are all injected into the gate terminal of the SiC module, so that the drain terminal voltage of the SiC module is clamped at a safety threshold V dth .
  2. 2. The SiC module over voltage clamp gate driver of claim 1, wherein: the drain clamping unit comprises a TVS diode VD1, a TVS diode VD2, a diode D1, a resistor R 1 and a resistor R 2 ; The cathode of the TVS diode VD1 is connected with the drain electrode of the SiC module; The anode of the TVS diode VD 1 is connected with one end of the resistor R 2 , the anode of the diode D1 and the cathode of the TVS diode VD 2 , and outputs an overvoltage fault signal V fal ; The anode of the TVS diode VD 2 is connected with the other end of the resistor R 2 to form a negative driving voltage V EE; The cathode of the diode D1 is connected with the grid electrode of the SiC module through a resistor R 1 .
  3. 3. The over-voltage clamped gate driver of a SiC MOSFET of claim 2, wherein the clamping current flows through a diode D1 in the drain clamping unit and a resistor R 1 to be injected into the gate of the SiC module, the resistance range of the resistor R 1 is below 10Ω, the resistance range of the resistor R 2 is above 100deg.OMEGA, and the maximum value of the clamping current is determined according to the breakdown peak current of VD 1.
  4. 4. The SiC module over voltage clamp gate driver of claim 1, wherein: The grid amplifier comprises a driver DR 1 , a driver DR 2 , an N-type triode Q g1 , a P-type triode Q g2 and a grid resistor R g ; The collector of the N-type triode Q g1 is connected with positive driving voltage V CC ; The emitter of the N-type triode Q g1 is connected with one end of an emitter and grid resistor R g of the P-type triode Q g2 ; The other end of the grid resistor R g is connected with the other end of the resistor R 1 and the grid of the SiC module, and the collector of the P-type triode Q g2 is connected with negative driving voltage V EE ; The base electrode of the N-type triode Q g1 is connected with the output end of the driver DR 1 ; The base of the P-type transistor Q g2 is connected to the output of the driver DR 2 .
  5. 5. The SiC module over voltage clamp gate driver of claim 1, wherein: The logic control unit comprises an AND gate G a1 and an OR gate G a2 ; the input end of the driver DR 1 is connected with the output end of the AND gate G a1 ; A first input end of the AND gate G a1 is connected with a positive driving voltage V CC ; The second input end of the AND gate G a1 is connected with the first input end of the OR gate G a2 , and receives a switching signal V PWM ; A second input terminal of the or gate G a2 receives an overvoltage fault signal V fal ; the output of the or gate G a2 is connected to the input of the driver DR 2 .
  6. 6. The SiC module over voltage clamp gate driver of claim 5, wherein: The AND gate G a1 comprises a resistor R 3 , a diode D 2 and a diode D 3 ; The OR gate G a2 comprises a resistor R 4 , a diode D 4 and a diode D 5 ; One end of the resistor R 3 is connected with positive driving voltage V CC ; The other end of the resistor R 3 is connected with the anode of the diode D 2 , the anode of the diode D 3 and the input end of the driver DR 1 ; The cathode of the diode D 3 is connected with the anode of the diode D 4 and receives a switching signal V PWM ; The cathode of the diode D 4 is connected with the cathode of the diode D 5 , the input end of the driver DR 2 and one end of the resistor R 4 ; The anode of the diode D 5 receives an overvoltage fault signal V fal ; The other end of the resistor R 4 and the cathode of the diode D 2 are grounded respectively.
  7. 7. The SiC module over-voltage clamp gate driver of claim 1, further comprising a fault latch unit connected to an output end of an over-voltage fault signal V fal of the drain clamp unit for locking the fault signal, supporting fault information reading, and emitting an optical signal or an electrical signal alarm when the over-voltage fault signal V fal is detected as a valid pulse; The fault latch unit comprises a NOT gate G a3 , a NOT gate G a4 , a NOT gate G a5 , an LED and a resistor R 3 ; The input end of the NOT gate G a3 receives a switching signal V PWM , and the output end of the NOT gate G a3 is connected with the first input end of the NOT gate G a4 ; The second input end of the NAND gate G a4 is connected with the output end of the NAND gate G a5 , and the output end of the NAND gate G a4 is connected with the first input end of the NAND gate G a5 and the anode of the LED and outputs an alarm signal V sig ; A second input of the nand gate G a5 receives an overvoltage fault signal V fal .
  8. 8. The SiC MOSFET over-voltage clamp gate driver of any one of claims 2 to 7, wherein the gate driver is further adapted for use with an IGBT or SiC MOSFET, wherein when used with an IGBT the drain clamp unit is connected to the collector of the IGBT, the gate amplifier is connected to the gate of the IGBT, wherein the over-voltage fault signal V fal corresponds to a collector-emitter over-voltage fault of the IGBT, and wherein the safety threshold V fal matches the collector-emitter rated withstand voltage value of the IGBT; When used in a SiC MOSFET, the drain clamp unit is connected to the drain of the SiC MOSFET, the gate amplifier is connected to the gate of the SiC MOSFET, the over-voltage fault signal V fal corresponds to the drain over-voltage fault of the SiC MOSFET, and the safety threshold V fal matches the drain rated withstand voltage value of the SiC MOSFET.
  9. 9. A SiC module over voltage clamp gate driving method, characterized in that it is performed using the SiC module over voltage clamp gate driver according to any one of claims 1 to 8, the method comprising: When the SiC module normally works, when the switching signal V PWM is at a high level, the AND gate G a1 outputs a high level to drive DR 1 to conduct the N-type triode Q g1 , the OR gate G a2 outputs a high level to drive DR 2 to cut off the P-type triode Q g2 , and when the switching signal V PWM is at a low level, the AND gate G a1 outputs a low level to cut off DR 1 and the N-type triode Q g1 , the OR gate G a2 outputs a low level to drive DR 2 to conduct the P-type triode Q g2 , and the SiC module is cut off; When a switching signal V PWM received by the SiC module is in a low level and enters a turn-off transient state, and the drain-source voltage V DS of the switching signal V PWM rises to a safety threshold value V dth , the TVS diode VD1 breaks down and is conducted, and a drain clamping unit generates a clamping current and an overvoltage fault signal V fal ; After the overvoltage fault signal V fal is input into the logic control unit, the output level of the OR gate G a2 is turned over, the DR 2 is driven to cut off the P-type triode Q g2 , the negative driving path of the gate amplifier is closed, and the clamping current is blocked to shunt to the gate amplifier; The clamping current is fully injected into the grid electrode of the SiC module through the diode D1 and the resistor R 1 , the grid electrode potential is raised, the SiC module is partially conducted to limit the drain-source voltage V DS to continuously rise, and finally the drain voltage is clamped at a safety threshold V dth .
  10. 10. A power module comprising the SiC module over voltage clamp gate driver of any one of claims 1-8.
  11. 11. A power conversion device comprising the SiC module over-voltage clamp gate driver according to any one of claims 1 to 8.

Description

SiC module overvoltage clamping grid driver, control method thereof and power conversion device Technical Field The invention belongs to the technical field of power electronics, and particularly relates to an over-voltage clamping grid driver of a SiC module, a control method thereof and a power conversion device. Background In recent years, wide bandgap semiconductor devices represented by silicon carbide (SiC) and gallium nitride (GaN) have been widely used in the fields of new energy automobiles, rail transit, industrial transmissions, new energy power generation, and the like, by virtue of their excellent characteristics of high switching frequency, high operating temperature, and high breakdown field strength. Particularly, siC modules are becoming the first choice for medium and high power applications because of their ability to significantly improve the efficiency and power density of power electronics systems. However, the fast switching characteristic of SiC modules is a double-edged sword. Extremely high switching speeds (dv/dt and di/dt) can lead to significant parasitic parametric effects, creating too high off overvoltage spikes, breaking down the SiC module. In order to solve the overvoltage problem, an overvoltage clamping protection circuit is commonly adopted in the industry. Conventional clamping circuits are typically implemented by a network of clamping diodes connected in parallel between the gate and drain of the power device. When the drain voltage is abnormally raised due to turn-off overshoot or loop parasitic inductance oscillation, the network is turned on, and the current generated by overvoltage (i.e., clamping current) is led to the gate, so that the gate potential is raised, and the device part is turned on, so that further rise of the drain voltage is limited. While active clamp circuits are effective in preventing over-voltage breakdown, they suffer from an inherent disadvantage of clamping current shunting issues particularly in high speed, high current applications. Specifically, when the clamp circuit is operated, the generated clamp current does not flow to the gate in its entirety, but is shunted to the source of the driver. This shunt problem can have a series of negative effects, the shunt resulting in a current reduction that is actually used to raise the gate voltage and thereby suppress the drain voltage. To achieve the desired clamping effect, a TVS tube of greater current rating may be required, adding cost and bulk. As current is shunted, the gate voltage build-up slows down, possibly resulting in a delay or insufficient clamping action, failing to accurately clamp the drain voltage to the target value. Even worse, insufficient clamping may cause a ringing of the drain voltage, which is continuously coupled to the gate through miller capacitance under certain conditions, causing resonance of the gate voltage, which may still eventually lead to intermittent false turn-on of the device, disabling protection. In summary, when the existing conventional clamping scheme is used for protecting the high-speed SiC module, the clamping efficiency is low, the action is inaccurate, and the potential reliability risks are inherent limitations due to the inherent clamping current shunt problem. Accordingly, there is a strong need in the art for a new gate drive scheme that overcomes the above-described drawbacks to achieve more efficient, accurate, and reliable overvoltage protection for SiC modules. Disclosure of Invention The invention aims to provide an over-voltage clamping grid driver of a SiC module, a control method thereof and a power conversion device, which are used for solving the problems in the background technology. According to the invention, when the SiC module has an off overvoltage fault, the gate driver triggers the clamping unit, clamping current is injected into the gate to raise the gate voltage, the logic control unit closes the gate amplifier based on the fed-back overvoltage fault signal, so that an additional shunt path of the clamping current is effectively blocked, the clamping current is ensured to be fully injected into the gate of the SiC module, and the suppression effect of overvoltage clamping is improved. In order to achieve the above object, the technical scheme of the present invention is as follows: In a first aspect, the invention provides an over-voltage clamped gate driver of a SiC module, wherein the SiC module integrates at least one SiC power chip and a packaging parasitic structure, and the over-voltage clamped gate driver comprises: The drain clamping unit is connected with a drain terminal of the SiC module and used for monitoring the drain-source voltage of the SiC module, clamping an overvoltage peak of a drain-source electrode of the SiC module at a safety threshold V dth and synchronously outputting an overvoltage fault signal V fal; The grid amplifier is electrically connected with a grid terminal of the SiC module and is