A New Approach to Evaluating Aging in Passive Networks of Traction Inverters via Impedance Variation

Ensuring electromagnetic compatibility in electric vehicles is crucial, along with minimizing DC bus voltage ripple caused by inverter switching to maintain system stability and performance. The circuit consisting of the electromagnetic interference filter and the DC-link capacitor is a passive network that represents one of the most critical systems of the inverter in terms of reliability. This paper presents a novel method for the characterization of DC-link capacitor aging and detection of electromagnetic interference filter degradation using impedance response analysis. This method enables distinguishing between the aging of the electromagnetic interference filter and the DC-link capacitor through a single measurement, without the need to open the inverter, requiring access only to the high-voltage DC terminals.