高速SiC MOSFET开关特性的测试方法

Test Method for Switching Performance of High Speed SiC MOSFET

为正确地评估高速SiC MOSFET的开关特性,基于双脉冲测试平台对精准的测试方法进行研究。首先,仿真证明电路中寄生电感对SiC MOSFET开关特性的影响,优化设计PCB布局以减小寄生电感,对比PCB布局优化前后的测试结果。其次,对比分析续流二极管的结电容以及负载电感的寄生电容对SiC MOSFET开通特性的影响。然后,对比分析使用不同带宽的非隔离电压探头、不同电压探头地线连接方式、不同电流测试设备对测试结果的影响,并说明电压与电流波形之间相位延迟对开关能量损耗的影响。最后,对比分析不同测试点对测试结果的影响。

In order to precisely test the switching performance of high speed SiC MOSFET,thispaper will focus on the precise test method in the double pulse test platform.The effects of the parasiticinductors on the switching performance are illustrated by simulation,and the PCB layout is optimizedto reduce the parasitic inductors.The tested results of two PCB layouts are compared.The effects of theparasitic capacitors in the flywheel diode and the load inductor on the turn-on switching performanceare presented.The tested results by different passive voltage probes,different grounding connectingways and different current test equipment are compared.The impacts of the phase delay on the turn-onand turn-off switching loss are presented.At last,the proper test points are shown clearly in this paper.