CN-121984486-A - Overcurrent protection method and device for silicon carbide power device and storage medium

CN121984486ACN 121984486 ACN121984486 ACN 121984486ACN-121984486-A

Abstract

The invention relates to the technical field of power electronic control, and discloses an overcurrent protection method and device for a silicon carbide power device, and a storage medium, wherein under the condition that the silicon carbide power device is driven to be conducted, the real-time current of the silicon carbide power device is obtained, the overcurrent property of the real-time current is judged, and a first preset current threshold value, a second preset current threshold value and a corresponding hot air risk assessment window period are correspondingly set in consideration of different thermal stress risks of the silicon carbide power device, therefore, when the real-time current is in the current interval between the first preset current threshold value and the second preset current threshold value, the silicon carbide power device can be driven in the hot air risk assessment window period, the active inhibition of wave-by-wave current limiting is realized, the current is creatively prevented from being forced to be converted to a high-loss body diode, the self-destruction type thermal damage or thermal failure problem easily caused on the silicon carbide power device is eliminated, and the overcurrent protection of the silicon carbide power device can be effectively and reliably realized.

Inventors

SHI WEI
LIU ZHONGWEI
XIAO ZHENGHU
SHI YAOHUA
TANG JIAYI

Assignees

西安图为电气技术有限公司

Dates

Publication Date: 20260505
Application Date: 20260324

Claims (9)

1. An overcurrent protection method for a silicon carbide power device, comprising the steps of: under the condition that the silicon carbide power device is driven to be conducted, acquiring real-time current flowing through the silicon carbide power device; When the real-time current is monitored to be larger than or equal to a first preset current threshold value and smaller than a second preset current threshold value, the silicon carbide power device is kept to be driven in a follow-up preset hot air risk assessment window period; Wherein the first preset current threshold is less than the second preset current threshold; The first preset current threshold is set according to the following conditions: the silicon carbide power device is continuously conducted in the hot air risk assessment window period with the first preset current threshold value to generate heat accumulation, and the heat accumulation risk initial value of the silicon carbide power device is continuously close to but not exceeding; The second preset current threshold is set according to the following conditions: And the silicon carbide power device is continuously conducted within the hot air risk assessment window period by the second preset current threshold value to generate heat accumulation, and the heat accumulation safety limit value of the silicon carbide power device is reached.
2. The method of claim 1, further comprising, during the hot blast risk assessment window period: continuously monitoring the real-time current of the silicon carbide power device until the whole hot air risk assessment window period is experienced; And under the condition that the whole hot air risk assessment window period is completed, when the real-time current at any moment in the hot air risk assessment window period is determined to be larger than or equal to the first preset current threshold value, turning off the silicon carbide power device, or when the real-time current at least one moment in the hot air risk assessment window period is determined to be smaller than the first preset current threshold value, maintaining driving the silicon carbide power device.
3. The method of overcurrent protection for a silicon carbide power device of claim 1, further comprising: and when the real-time current is monitored to be greater than or equal to the second preset current threshold, performing wave-by-wave current limiting on the silicon carbide power device.
4. The method of claim 3, further comprising, in the case of wave-by-wave current limiting of the silicon carbide power device: Starting an emergency counter, and adding 1 to the count value of the emergency counter every time the emergency counter goes through the switching period of the silicon carbide power device; And when the count value of the emergency counter reaches a preset count threshold, turning off the silicon carbide power device.
5. The method of overcurrent protection for a silicon carbide power device of claim 1, further comprising: continuously monitoring the real-time junction temperature of the silicon carbide power device in the hot air risk assessment window period; and when the real-time junction temperature at a certain moment is monitored to reach a preset target junction temperature, turning off the silicon carbide power device.
6. The method of any one of claims 1 to 5, wherein the hot risk assessment window period employs N switching cycles of the silicon carbide power device, where N is related to a thermal capacity of the silicon carbide power device, a specific power loss, where the specific power loss is generated by a body diode of the silicon carbide power device if the real-time current is the first preset current threshold.
7. An overcurrent protection device for a silicon carbide power device, comprising: The current sampling unit is used for acquiring real-time current flowing through the silicon carbide power device under the condition that the silicon carbide power device is driven to be conducted; The driving control unit is used for maintaining driving of the silicon carbide power device in a follow-up preset hot air risk assessment window period when the real-time current is monitored to be larger than or equal to a first preset current threshold value and smaller than a second preset current threshold value; Wherein the first preset current threshold is less than the second preset current threshold; The first preset current threshold is set according to the following conditions: the silicon carbide power device is continuously conducted in the hot air risk assessment window period with the first preset current threshold value to generate heat accumulation, and the heat accumulation risk initial value of the silicon carbide power device is continuously close to but not exceeding; The second preset current threshold is set according to the following conditions: And the silicon carbide power device is continuously conducted within the hot air risk assessment window period by the second preset current threshold value to generate heat accumulation, and the heat accumulation safety limit value of the silicon carbide power device is reached.
8. An electronic device, comprising: At least one processor; At least one memory for storing at least one program; The method of over-current protection of a silicon carbide power device according to any one of claims 1 to 6, when at least one of said programs is executed by at least one of said processors.
9. A computer-readable storage medium, in which a processor-executable program is stored, which when executed by a processor is configured to implement the overcurrent protection method of the silicon carbide power device according to any one of claims 1 to 6.

Description

Overcurrent protection method and device for silicon carbide power device and storage medium Technical Field The invention relates to the technical field of power electronic control, in particular to an overcurrent protection method and device for a silicon carbide power device and a storage medium. Background In a power converter based on silicon-based Insulated Gate Bipolar Transistors (IGBTs), the "step-by-step current limiting" is a classical and efficient overcurrent protection method, the basic principle of which is to detect the current of a power device in real time in each switching period, once a set threshold is exceeded, immediately force the rest of the drive signal in the period to turn off, forcing the current to commutate to a freewheeling diode in anti-parallel with the IGBTs, which is an independent device optimized for efficient conduction, with a low forward voltage drop, so that the protection method effectively limits the current peak without introducing unacceptable additional losses. However, with the development of wide bandgap semiconductor devices, especially the widespread application of silicon carbide power devices, the above method is no longer suitable, when a wave-by-wave current limiting protection is applied to a silicon carbide power device, current is forced to be commutated from a low-resistance MOSFET channel to a high-loss body diode, so under the condition of high current, the instantaneous power consumption generated by the body diode is extremely huge, thereby leading to the rapid rise of the junction temperature of the silicon carbide power device in a short time, and on the contrary, the thermal damage or thermal failure of the device is caused by the protection action. Disclosure of Invention The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the invention provides an overcurrent protection method and device for a silicon carbide power device and a storage medium, and the overcurrent protection method and device for the silicon carbide power device can effectively and reliably realize the overcurrent protection of the silicon carbide power device. In a first aspect, an embodiment of the present invention provides an overcurrent protection method for a silicon carbide power device, including: under the condition that the silicon carbide power device is driven to be conducted, acquiring real-time current flowing through the silicon carbide power device; When the real-time current is monitored to be larger than or equal to a first preset current threshold value and smaller than a second preset current threshold value, the silicon carbide power device is kept to be driven in a follow-up preset hot air risk assessment window period; Wherein the first preset current threshold is less than the second preset current threshold; The first preset current threshold is set according to the following conditions: the silicon carbide power device is continuously conducted in the hot air risk assessment window period with the first preset current threshold value to generate heat accumulation, and the heat accumulation risk initial value of the silicon carbide power device is continuously close to but not exceeding; The second preset current threshold is set according to the following conditions: And the silicon carbide power device is continuously conducted within the hot air risk assessment window period by the second preset current threshold value to generate heat accumulation, and the heat accumulation safety limit value of the silicon carbide power device is reached. Optionally, in one embodiment of the present invention, during the hot air risk assessment window period, the method further includes: continuously monitoring the real-time current of the silicon carbide power device until the whole hot air risk assessment window period is experienced; And under the condition that the whole hot air risk assessment window period is completed, when the real-time current at any moment in the hot air risk assessment window period is determined to be larger than or equal to the first preset current threshold value, turning off the silicon carbide power device, or when the real-time current at least one moment in the hot air risk assessment window period is determined to be smaller than the first preset current threshold value, maintaining driving the silicon carbide power device. Optionally, in one embodiment of the present invention, the method further includes: and when the real-time current is monitored to be greater than or equal to the second preset current threshold, performing wave-by-wave current limiting on the silicon carbide power device. Optionally, in an embodiment of the present invention, in a case of performing wave-by-wave current limiting on the silicon carbide power device, the method further includes: Starting an emergency counter, and adding 1 to the count value of the emergency counter every t