Characterization of aging process in power converters using spread spectrum time domain reflectometry

Abstract

Figure 1. The proposed technique to identify aging of various components using reflectometry without altering the main power flow of the converter.Abstract-This paper aims to find a new technique to predict the state of health of power converters by characterizing the most vulnerable components in the converter without affecting the normal circuit operation. Spread spectrum time domain reflectometry (SSTDR) can detect most of the aged components inside the converter while the converter is operational. Semiconductor switches and electrolytic capacitors are the two most sensitive components in power converter circuits, and this paper demonstrated how SSTDR can be used to determine the degradation of these components. Multiple sets of test data have been generated while the SSTDR process is applied to the power MOSFETs, IGBTs connected in a chopper circuit and to the aluminum electrolytic capacitors connected in an RC circuit. Analysis is done on these obtained test data to show how the SSTDR generated data are consistent with the aging of power MOSFETs, IGBTs and electrolytic capacitors. I.978-1-4673-0803-8/12/$31.00 ©2012 IEEE

Quantifying Device Degradation in Live Power Converters Using SSTDR Assisted Impedance Matrix

“…Other than the MOSFET, the key measurable quantities to estimate the aging in individual components are-capacitor ESR and capacitance, V C E of IGBTs, and gate characteristics of IGBTs [5]. The authors believe that there exist other measurable quantities that could be used to estimate aging in components, and the ongoing research and the collaboration with Sandia National Lab should provide the necessary information to identify those quantities.…”

“…As an added feature, several faults inside the circuit can be identified without interrupting the circuit's normal operation although the discussion on this capability of SSTDR (fault detection) is beyond the scope of this paper. Authors' previous work demonstrated how SSTDR can be applied to identify degradation in MOSFETs, IGBTs, and electrolytic capacitors [5]. Once the component level analysis was done, authors are particularly interested in the reliability estimation of a converter circuit using the SSTDR generated data.…”