SiC MOSFET short-circuit protection circuit and protection method for comprehensively comparing grid charges and voltages

Abstract

The invention discloses a SiC MOSFET short-circuit protection circuit and method for comprehensively comparing grid charges and voltages. The SiC MOSFET short-circuit protection circuit comprises a logic processing circuit, a grid charge comparison circuit, a grid voltage comparison circuit and a driving circuit. Whether SiC MOSFET is short-circuited or not is judged by comparing logic signals output by the gate charge comparison circuit and the gate voltage comparison circuit; when a short circuit occurs, the gate voltage comparison circuit and the gate charge comparison circuit output high levels in sequence, and the logic circuit clamps the gate of the SiC MOSFET to a driving negative voltage, thereby realizing quick turn-off of the switching tube, and suppressing a short-circuit current before the switching tube is completely turned on. According to the invention, the damage of a short-circuit fault to a device is reduced, the performance advantage of the SiC MOSFET in playing a high-speed switch is not influenced, and the normal work of the SiC MOSFET is not influenced.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a SiC MOSFET short-circuit protection circuit and a protection method for comprehensively comparing gate charge and voltage. Background technique [0002] Compared with traditional silicon (Si) devices, silicon carbide (SiC) devices have wider bandgap, higher thermal conductivity, higher critical field strength and faster saturation electron mobility, and their turn-on voltage It has the characteristics of high temperature resistance and high pressure resistance, so it has great application prospects in the fields of aerospace, hybrid electric vehicles, solar inverters, power factor correction, UPS and motor drives. [0003] However, in practical applications, on the one hand, power devices will inevitably work in abnormal working conditions such as overload and short circuit, and there is a certain delay in the protection circuit from detection to action, w...

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Problems solved by technology

[0005] Purpose of the invention: In order to solve the problems of low precision, long response time, and high cost in the prior art, we provide a SiC MOSFET short-circuit protection circuit and protection method that comprehensively compares gate charge and voltage

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