中文说明：
研究了电力电子电路中关键元器件，如电解电容、功率 MOSFET、功率二极管、电感等的失效机理及故障模型，分析了能够表征元器件失效的故障特征参数，并确定特征参数的阈值；通过分析元器件及电路在退化过程中电路各输出参数的变化情况，定义输出电压偏移率作为表征电路性能退化的特征参数。
English Description：
The key components of power electronic circuit, such as electrolytic capacitor and power supply, are studied Based on the failure mechanism and fault model of MOSFET, power diode and inductor, the fault characteristic parameters which can characterize the failure of components are analyzed, and the threshold value of characteristic parameters is determined. By analyzing the changes of circuit output parameters in the degradation process of components and circuits, the output voltage offset rate is defined as the characteristic parameter of circuit performance degradation.