Open-loop driving circuit for optimizing silicon carbide MOSFET turn-on waveform

Abstract

The invention discloses an open-loop driving circuit for optimizing silicon carbide MOSFET turn-on waveform. The circuit comprises a driving voltage waveform generator for producing driving voltage waveform of a preset rising edge; a gate pole changing driving resistance control circuit for controlling the size of the gate pole driving resistance at different stages of the turn-on transient process, wherein the grid source voltage change rate of the silicon carbide is in consistent with the driving voltage rising change rate at the current rising stage, thereby controlling the current rising change rate and reverse current by controlling the driving voltage rising change rate; the gate pole current is increase at the voltage falling stage, thereby accelerating the voltage falling process and reducing the turn-on loss; the gate pole damping resistance is increased at the breakover-stabilizing stage, thereby suppressing the gate pole voltage overshooting without influencing the on-off speed. The driving circuit is simple in structure, easy to realize, low in cost, and capable of suppressing the reverse current peak and the gate pole voltage overshooting under the condition of reducing the turn-on loss.

Description

technical field [0001] The invention relates to the technical field of power electronic circuits, in particular to an open-loop drive circuit for optimizing the turn-on waveform of a silicon carbide MOSFET. Background technique [0002] Silicon carbide MOSFET is a new type of power semiconductor, and there is still a certain distance from large-scale industrialization. Due to the fast switching speed of silicon carbide devices, the gate voltage will have more serious gate oscillation and overshoot, which may break down the gate oxide layer and cause permanent failure of the device. The larger current change rate will bring more serious electromagnetic interference and Large turn-on reverse current. Although CREE and other manufacturers provide drivers, the driver can only change the switching transient process of SiC MOSFET by changing the gate resistance, and can only balance the compromise of gate voltage overshoot and switching loss, switching speed and switching loss, a...

AI Technical Summary

Problems solved by technology

[0008] 2) The gate voltage overshoot is serious, and the gate voltage overshoot usually exists in the t3-t4 stage, and the gate damping resistance in this stage is R gon The equivalent resistance connected in parallel with Rbst, the damping is smaller, and the gate voltage spike will be larger

Closed-loop drive has disadvantages such as complex circuit, high cost, and detection circuit is susceptible to interference.

Although the open-loop drive circuit has the advantages of simple circuit and easy implementation, it is difficult for the current open-loop drive to suppress the reverse current peak and gate voltage overshoot while optimizing the turn-on loss.

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