基于PZT压电陶瓷的SiC MOSFET缓冲吸收电路

Snubber Circuit for SiC MOSFET Application Via PZT Piezoelectric Ceramic

在高速关断过程中,碳化硅(silicon carbide,SiC)金属-氧化物半导体场效应晶体管器件呈现出严重的电压过冲和振荡,降低器件电压裕量。通常,采用缓冲吸收电路改善SiC器件的关断电压轨迹。然而,现有研究忽略SiC器件与吸收电路的交互规律和工作温度对吸收电路性能的影响,限制缓冲吸收电路的应用。针对这些问题,该文提出一种基于锆钛酸铅(lead zirconate titanate,PZT)压电陶瓷的缓冲吸收电路,分析PZT的温度特性,通过建立半桥电路与PZT缓冲吸收电路的高精度交互模型,揭示PZT缓冲吸收电路与SiC器件的耦合规律,利用特征方程-根轨迹方法,定量刻画PZT缓冲吸收电路的参数设计域。对比评估工作温度对多种缓冲吸收电路性能的影响。实验结果表明,所提设计方法能很好地抑制关断电压过冲与振荡,验证设计方法的有效性。相较于传统RC缓冲吸收电路,PZT缓冲吸收电路在工作温度发生变动后,仍然具有很好的抑制效果,且抑制效果随工作温度的上升而不断增强。为SiC功率器件的暂态稳定性分析,以及功率模块和缓冲吸收电路的集成设计,提供有益的参考。

Thesiliconcarbide(SiC)metal-oxidesemiconductor rfield-effect transistor(MOSFET)exhibits serious voltage overshooting and oscillation during high-speed turn-off,which reduces the voltage margin of the device.The snubber circuit is usually utilized to regulate the turn-off voltage trajectory of the SiC device.However,the existing researches overlook the interaction between the SiC device and the snubber and ignore the temperature-dependent properties of the snubber,which limits the application of the snubber circuit.Motivated by these issues,this paper proposes a novel snubber circuit based on the lead zirconate titanate(PZT)piezoelectric ceramic.With the aid of the temperature characteristics of the PZT,the in-depth interaction models between the half-bridge topology and the PZT snubber are created.Moreover,based on the characteristic equation-root locus tool,the coupling principles of the SiC device and PZT snubber are quantitatively demonstrated.Additionally,the temperature-dependent performances of multiple snubber circuits are assessed.Comprehensive experimental resultssensure thatthe overshooting and oscillation of the turn-off voltage can be well suppressed by using the target-designed PZT,which verifies the accuracy of the design method.Different from the traditional RC snubber,it is preferred that the suppression effect of the PZT snubber is enhanced under the increased ambient temperature.The models and findings might promote the stability analysis of the SiC MOSFET and the packaging integration of the power module with the snubber circuit.