A detection device for igbt desaturation fault

Abstract

The application discloses a detection device for IGBT desaturation fault, which includes a logic processing circuit connected to a signal channel, a MOS transistor, a first diode and a signal output circuit. The logic processing circuit is connected with the signal channel, and is used to output a turn-on control signal to the gate of the MOS tube when the pulse width modulation signal is at a low level, and output a cut-off control signal to the gate of the MOS tube when the pulse width modulation signal is at a high level; the drain of the MOS tube It is connected to the anode of the first diode, and the source is grounded; the cathode of the first diode is connected to the C pole of the IGBT to be detected, and the anode is connected to the signal output circuit. The high-level signal of the anode of the first diode is used for used as a desaturation fault signal; the signal output circuit is used to signally connect the anode of the first diode to the protection processing unit of the IGBT to be detected. In this solution, when the pulse width modulation signal is at low level, the anode of the diode used to output the desaturation fault signal is forcibly pulled down through the MOS tube, thereby ensuring that false alarms will not occur during the desaturation fault inspection of the IGBT.

Description

technical field [0001] The present application relates to the field of electrical technology, and more specifically, to a detection device for IGBT desaturation faults. Background technique [0002] IGBT generally works in the saturation region and cut-off region during normal operation, which is equivalent to the role of a switch. When working in the protection region, Vce is low and the change is small. When the external circuit is short-circuited, it flows through the C level of the IGBT. The current between the E-level and the E-level will increase to a certain extent, and the IGBT will exit the saturation zone and re-enter the linear zone. At this time, the Vce will suddenly change greatly and at the same time, a large Ice will flow. It can be known from the power formula that the IGBT at this time The loss will be very large, if the IGBT is not blocked in time, it will burn out quickly. Generally, the driving module of the IGBT is provided with a protection circuit, w...

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Problems solved by technology

[0005] It can be seen from the above description that this technical solution is extremely prone to false alarms due to the many situations that the circuit needs to deal with and the complex structure, which affects the normal operation of the IGBT

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