IGBT short circuit detection circuit and frequency converter

Abstract

The invention relates to an IGBT short circuit detection circuit and a frequency converter. The IGBT short circuit detection circuit comprises a bias current source, a discharge loop and a voltage comparison circuit. The input end of the bias current source is connected with the output end of a driving branch for driving the IGBT; the input end of the discharge loop is connected with the output end of the bias current source, and the output end of the discharge loop is connected with the collector electrode of the IGBT and is used for providing a discharge channel for the bias current source when the IGBT is conducted; the first input end of the voltage comparison circuit is respectively connected with the input end of the discharge loop and the output end of the bias current source and is used for comparing a first voltage signal input by the first input end with a reference voltage signal input by the second input end so as to detect whether the IGBT is short-circuited or not; the power supply voltage of the driving branch is the same as the power supply voltage of the voltage comparison circuit. According to the invention, the negative voltage output when the IGBT is turned off by the driving branch is the power ground for the voltage comparison circuit, the input end of the voltage comparison circuit is not abnormal, and the problem of abnormal damage of the detection circuit caused by improper design is solved.

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