A large-power IGBT fault diagnosis and protection method and apparatus based on gate charges Q[g]

Abstract

The invention provides a large-power IGBT fault diagnosis and protection method and apparatus based on gate charges Q[g]. The method comprises the steps of collecting a gate current signal of an IGBT;performing integrating and resetting operation the collected IGBT gate current signal to obtain a gate charge analog signal Q[g] of the IGBT in different switching intervals; converting the obtainedgate charge analog signal Q[g] into a digital signal; performing real-time monitoring of the gate charges of the IGBT in the different switching intervals and comparing the monitored gate charges withthe gate charges in corresponding switching intervals in the normal switching states; and the specific fault type is judged according to the comparison result, and the fault type information is output; according to the fault type information, the IGBT is directly turned off, or the fault information is transmitted to an upper computer which will turn off the IGBT, thereby realizing rapid system protection and safe shutdown. Through the utilization of the method and apparatus of the invention, IGBT self-check and on-line real-time monitoring before power-on can be realized, thereby substantially reducing the risk of IGBT damages.

Description

technical field [0001] The invention relates to a high-power IGBT fault diagnosis and protection method, in particular to a method based on gate charge Q g High-power IGBT fault diagnosis and protection method. Background technique [0002] Insulated Gated Bipolar Transistor (IGBT) is a fully voltage-controlled power semiconductor device widely used in medium to high-power power electronic equipment. It combines the advantages of power transistor (GTR) and metal oxide semiconductor field effect transistor (MOSFET), and has the advantages of high switching frequency, simple driving circuit, high input impedance and low output impedance. [0003] Relevant studies have proved that about 34% of power electronic system failures are caused by the failure of power devices IGBT. It can be seen that the failure of main power devices is the main reason for the failure of power electronic systems. Therefore, it is of great significance to study the protection and fault diagnosis meth...

AI Technical Summary

Problems solved by technology

However, with the development of power semiconductor technology, the thermal capacity parameters of the IGBT chip gradually decrease, resulting in a decrease in its short-circuit withstand capability, so higher requirements are placed on the IGBT short-circuit protection time

[0005] At present, the research hotspots on IGBT open-circuit faults are basically based on software algorithms. Such methods need to occupy CPU resources, and the diagnosis time is relatively long, which is not conducive to the reliable operation of the system.

At the same time, the causes of IGBT open-circuit faults are different, and the fault phenomena and impacts are different. Therefore, for IGBT open-circuit faults, it is expected to identify the fault at the fastest speed, and it is necessary to accurately locate the cause of the fault.

[0006] There are many types of IGBT faults. Existing IGBT drive technology is limited to short-circuit faults for fault diagnosis. However, in fact, there are many types of short-circuit faults in IGBTs. If the specific fault types of IGBTs can be further distinguished, it is of great significance for fault analysis.

Moreover, the existing IGBT drive technology rarely has diagnosis for overcurrent protection and open circuit protection fault types. Although the open circuit fault of the IGBT will not cause the system to crash immediately, it will reduce the performance of the system. If it is not found in time, it will cause bigger accident

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