Protection circuit with function of high-speed IGBT short-circuit fault detection

Abstract

The invention relates to a protection circuit with the function of high-speed IGBT short-circuit fault detection. The protection circuit comprises a detection control circuit, an HSF short-circuit detection circuit, a FUL short-circuit detection circuit, an OR gate logic circuit, a gate drive circuit, a soft shutdown circuit and a gate resistor RG. In addition, the invention also discloses a method for protecting an IGBT short-circuit fault. According to the invention, two kinds of short-circuit types of a hard switch short-circuit fault and a loaded short-circuit fault and corresponding detection circuits are provided; a detection control circuit is set and the working states of the short-circuit detection circuits are controlled. The soft shutdown circuit carries out short-circuit shutdown processing on the IGBT and an output signal of the drive circuit is locked. According to the invention, the gate voltage VGE and the driving voltage VGG are detected. The detection circuit is simple and the short-circuit detection time is short. The short-circuit fault can be processed quickly and reliably; and the power device is effectively protected.

Description

technical field [0001] The invention belongs to the field of drive protection of power switching devices, and in particular relates to a short-circuit protection method and circuit using IGBT as a power switching device. Background technique [0002] Insulated Gate Bipolar Transistor (IGBT) has the advantages of on-state voltage drop, large current capacity, high input impedance, fast response, and simple control. Widely used in power electronic equipment. However, various faults are prone to occur when the power device IGBT is applied, and the IGBT short-circuit fault is one of the most common faults. Under normal circumstances, IGBT short-circuit faults can be divided into two categories, hard switching short-circuit fault (HSF, Hard Switching Fault) and load short-circuit fault (FUL, Fault UnderLoad). When the IGBT is turned on, the loop impedance is quite small. The on-load short-circuit fault refers to the short-circuit of the load after the IGBT has been turned on a...

AI Technical Summary

Problems solved by technology

The disadvantages of this short-circuit detection and protection scheme are: firstly, the circuit is not isolated from the power stage, and false detection is prone to occur; secondly, due to the existence of the delay circuit 1, the circuit needs a blanking time of 1~5us before the detection circuit can detect the short-circuit fault , so the HSF short-circuit fault cannot be quickly detected, and the short-circuit detection time is longer, which increases the risk of IGBT damage

Gate charge sensing circuit output voltag...

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