寄生电感对碳化硅MOSFET开关特性的影响

相比于传统的Si IGBT功率器件而言,碳化硅MOSFET可达到更高的开关频率、更高的工作温度以及更低的功率损耗.然而,快速的暂态过程使开关性能对回路的寄生参数更加敏感.因此,为了评估寄生电感对碳化硅MOSFET开关性能的影响,基于回路电感的概念,将栅极回路寄生电感、功率回路寄生电感以及共源极寄生电感等效成3个集总电感,并且从关断过电压、开通过电流及开关损耗等3个方面,对这3个电感对SiC MOSFET开关性能的影响进行了系统的对比研究.研究表明:共源极寄生电感对开关的影响最大,功率回路寄生电感次之,而栅极回路寄生电感影响最小.最后,基于实验分析结果,为高速开关电路的布局提出了一些值得借鉴的意见.

Effect of the Parasitic Inductance on SiC MOSFET Switching Characteristics

Compared with traditional silicon IGBT power devices,the SiC MOSFET can achieve higher switching frequency,bear higher operating temperature and produce lower power consumption.However,due to the faster switching transient process,the SiC MOSFET is more susceptive to the loop circuit parasitic parameters.Therefore,in order to assess the effect of the parasitic induc-tance on switching performance of the SiC MOSFET,the gate loop parasitic inductance,power loop parasitic induc-tance and common source parasitic inductance were equivalent to as the three lumped inductance elements according to the concept of the loop inductance,and then the effects of different parasitic induc-tances on the switching characteristics of the SiC MOSFET were systematically contrasted and studied in terms of turn-off voltage overshoot,turn-on current overshoot and switching losses.The research results show that the common source parasitic inductance has the greatest influence on the switch,the power loop parasitic inductance followed by,and the gate loop has the least effect.Finally,based on the experimental analysis results,some suggestions worthy of reference are put forward for the layout of high speed switching circuit.