Degradation Diagnosis of Power Module Based on Frequency Characteristics in Heat Flow

With the growing demand for highly reliable power electronic systems, the degradation diagnosis of the power modules is becoming increasingly important. Due to its multilayer structure and complex operating conditions, power modules are subject to several different degradation mechanisms and locations. However, most existing approaches for degradation diagnosis are designed to identify only one particular type of degradation. In this article, a novel approach for diagnosing degradations in power modules is proposed based on the frequency-domain heat flow spectrum analysis. Different degradation modes can be clearly distinguished based on the discovery that the frequency-domain heat flow characteristics will change in different frequency bands under different locations of degradation. Simulations and experiments are provided to validate the proposed analysis and method.