Gate turn-off control method and device of silicon carbide field effect transistor and driving circuit

Abstract

The invention discloses a grid turn-off control method. The grid turn-off control method comprises the steps of obtaining parasitic parameters of a silicon carbide field effect transistor; judging themonotonous relationship between the overshoot voltage and the gate turn-off voltage of the silicon carbide field effect transistor according to the parasitic parameters; determining an optimal valueof the gate turn-off voltage in a preset value interval according to the monotonic relationship, wherein the gate turn-off voltage enables the overshoot voltage to obtain the minimum value in the interval at the optimal value; and outputting the gate turn-off voltage with the optimal value to the gate of the silicon carbide field effect transistor so as to turn off the silicon carbide field effecttransistor. According to the invention, the gate turn-off voltage with a small overshoot voltage value is selected to carry out turn-off control on the silicon carbide field effect transistor, so that the crosstalk problem is solved, the drain-source voltage oscillation can be effectively inhibited, the device damage phenomenon caused by overshoot voltage is avoided, and the circuit operation safety is ensured. The invention also discloses a gate turn-off control device of the silicon carbide field effect transistor and a driving circuit, which also have the above beneficial effects.

Description

technical field [0001] The present application relates to the technical field of power electronics, in particular to a gate turn-off control method and device for a silicon carbide field effect transistor, and in particular to a driving circuit for a silicon carbide field effect transistor. Background technique [0002] SiC-based power electronic devices can effectively improve the performance of power electronic converters such as efficiency and power density due to their excellent characteristics such as high frequency, high voltage resistance, and high temperature resistance. However, as the device switching frequency increases, the rate of change of voltage and current during the switching process also increases. The existence of parasitic inductance and parasitic capacitance causes severe oscillation of the switching waveform, and device stress, electromagnetic interference (EMI) and switching tubes Loss is a serious problem. Since the gate threshold voltage of silicon...

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Problems solved by technology

However, as for the most suitable gate turn-off voltage, there is no specific solution given in the prior art. In fact, different gate turn-off voltages will affect the performance of SiC FETs. Overshoot voltage, once the overshoot voltage is too large, the risk of device damage will increase

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