基于驱动电流动态调节的低过冲低损耗SiC MOSFET有源门极驱动

Low Overshoot and Low Loss Active Gate Driver for SiC MOSFET Based on Driving Current Dynamic Regulation

与硅基功率器件相比,碳化硅(silicon carbide,SiC)MOSFET具有开关速度更快、导通损耗更低等优点,将越来越广泛的应用于高效高功率密度场合。但是,其开关特性对寄生参数非常敏感,在高速开关过程中极易产生瞬态电压电流尖峰和高频开关振荡,严重威胁Si C基变换器的可靠运行。针对这一问题,文中对SiC MOSFET的开关暂态过程进行深入分析,揭示门极驱动电流对开关过程电压电流过冲、振荡与开关损耗的影响机理。在此基础上,提出一种驱动电流分段动态调节的SiC MOSFET有源门极驱动电路,即根据开关过程不同阶段的状态反馈动态调整器件门极驱动电流。实验结果表明,所提出的方法能够在维持低开关损耗的同时,实现了对SiC MOSFET开关过程中电压电流过冲和高频振荡的有效抑制,提升SiC基电力电子装置的动态性能与运行可靠性。

Compared with silicon-based power devices, silicon carbide(SiC) MOSFETs featuring higher switching speed and lower losses, which will be more and more widely used in high efficiency and high power density applications. However, the switching characteristics of SiC MOSFET are very sensitive to parasitic parameters. In the process of high-speed switching, SiC MOSFET is prone to transient voltage and current spikes and high-frequency switching oscillations, which seriously threaten the reliable operation of SiC-based converters. To solve this problem, this paper conducted an in-depth analysis of the switching transient process of the SiC MOSFET, and revealed the influence mechanism of the gate drive current on overshoot, oscillation and switching losses. On this basis, an active gate driver for SiC MOSFET with segmented dynamic adjustment of drive current was proposed, which dynamically adjusted the gate drive current of the power device according to the state feedback at different stages of the switching process. Experimental results show that the proposed method can effectively suppress the voltage and current overshoot and high frequency oscillation during the switching process of SiC MOSFET while maintain low switching losses, and improve the dynamical performance and reliability of SiC-based converters.