SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) self-adaptive driving circuit and self-adaptive driving method

Abstract

The invention discloses a SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) self-adaptive driving circuit and a self-adaptive driving method. An embedded system inputs PWM, the PWM1 and the PWM2 are output; the PWM1 and the PWM2 are respectively and correspondingly connected with the base electrodes of the NPN tube and the PNP tube through an isolation amplifying circuit; collector electrodes of the NPN transistor and the PNP transistor are correspondingly connected with a positive electrode end and a negative electrode end of a power supply respectively, emitting electrodes of the NPN transistor and the PNP transistor are connected with gate electrodes of the SiC MOSFETs, and source electrodes of the SiC MOSFETs are grounded. Respectively obtaining a current change rate and avoltage change rate of a drain electrode of the SiC MOSFET through the isolation sampling circuit and the differentiating circuit; wherein the embedded system is used for controlling the voltage of the drain electrode of the SiC MOSFET according to the level of PWM and the current change rate and the voltage change rate of the drain electrode of the SiC MOSFET; and the pulse widths of the PWM1 and the PWM2 are adjusted in real time, so that the peak current or surge voltage generated in the switching process of the SiC MOSFET is effectively adjusted and controlled, and the self-adaptive quickon-off operation of the SiC MOSFET is realized.

Description

technical field [0001] The invention relates to the technical field of power electronics, and more specifically relates to a SiC MOSFET self-adaptive drive circuit and a drive method. Background technique [0002] SiC MOSFET is a voltage-driven switching device, which has the characteristics of fast on-off speed, high withstand voltage and low on-resistance, and has a high operating frequency. A large peak current is likely to be generated during the fast turn-on process, and a large surge voltage is likely to be generated during the fast turn-off process, causing the SiC MOSFET operating track to exceed the safe operating area (SOA), thereby affecting the reliability and reliability of the SiC MOSFET itself. Safety, and at the same time, it will also cause serious electromagnetic interference to external devices. [0003] Based on this, the method of increasing the resistance value of the gate drive resistor is usually used to reduce the peak current when the SiC MOSFET is...

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Problems solved by technology

[0002] SiC MOSFET is a voltage-driven switching device, which has the characteristics of fast on-off speed, high withstand voltage and low on-resistance, and has a high operating frequency. A large peak current is likely to be generated during the fast turn-on process, and a large surge voltage is likely to be generated during the fast turn-off process, causing the SiC MOSFET operating track to exceed the safe operating area (SOA), thereby affecting the reliability and reliability of the SiC MOSFET itself. security, and will also cause serious electromagnetic interference to external devices

[0003] Based on this, the method of increasing the resistance value of the gate drive resistor is usually used to reduce the peak current when the SiC MOSFET is turned on, but this method reduces the turn-on speed of the SiC MOSFET and also increases the conduction loss; usually outside the SiC MOSFET Add a snubber circuit to reduce the surge voltage when the SiC MOSFET is turned off, but this method increases the difficulty and cost of implementation, and the snubber circuit itself also has energy loss

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