共源极电感对SiC MOSFET开关损耗影响的研究

Impact of Common Source Inductance on Switching Loss of SiC MOSFET

共源极电感同时存在于功率MOSFET的功率回路和门极驱动回路中,影响器件的开关特性和开关损耗。共源极电感的影响将随着器件开关速度和开关频率的提高而显得更为严重。碳化硅(SiC)MOSFET相对于硅器件的材料优势使其可以实现更快速的开关过程,共源极电感的影响更加需要考虑。首先分析了现有功率开关损耗测量方法的优劣,然后选用一种通过测量结温升和热阻的方法来测量SiC MOSFET的开关损耗,最后搭建了一台输出功率1kW、输出电压800V的全碳化硅Boost样机,从100kHz到500kHz进行实验验证。实验结果表明,当不含共源极电感时SiC MOSFET的开通损耗、关断损耗均有所减小。

Common source inductance（CSI） exists both on the power loop and the gate driver loop of a power electronic circuit, impacting the switching characteristics and losses of devices. The higher the switching speed and frequency is, the severer the impact is. SiC MOSFETs can switch much faster compared to its Si-based counterpart due to its material superiority, so it＇s more important to study the impact of common source inductance on switching loss of SiC MOSFET. First, the benefits and drawbacks of common means to measure device switching loss is in this paper analyzed,then a method of measuring temperature rise and thermal resistance is adopted. Finally, a 1 k W, 800 V output all-SiC boost DC-DC converter is built to accomplish this study, and the converter works from 100 k Hz to 500 k Hz at intervals of 100 k Hz. The experiment results show that the turn on loss and turn off loss will be reduced when eliminating the common source inductance.