Condition Monitoring for Discrete Packaged Insulated Gate Bipolar Transistors in Power Converters
Extensive utilization of insulated gate bipolar transistor (IGBTs) in the power converters has significantly increased concerns over its reliability. Failure of such critical component eventually cause unexpected shut downs and even lead to catastrophic faults resulting in huge economic loss. So, tools for incipient fault diagnosis and aging prognosis have to be utilized for reducing the risk of faults and accidents. Yet, established tools are not mature enough and there exist a major reliability gap exist in condition monitoring of IGBTs. In order to improve current prognostic and diagnostic tools, this dissertation investigates ongoing aging induced degradation and corresponding shifts in electrical parameters for IGBTs. Such useful electrical parameters are referred as aging precursors which are obtained after extensive thermal aging tests. Based on the aging test results, aging precursors are identified and an in-situ condition monitoring circuit has been proposed as well. Due to low component count, the proposed circuit is cost effective and can be easily integrated to conventional gate driver circuits. Based on the data measurements, further remaining useful lifetime estimation for IGBTs have been carried out as well. It is conceived that such tools lay foundations for smart-energy conversion systems which are self-capable in evaluating the degradation information using aging precursors to prevent imminent failures in the system. Briefly, this dissertation discusses: o identification and characterization of aging precursors, o development of innovate and easy-to-integrate condition monitoring circuit o development of remaining useful lifetime estimation tool based on the monitored data for advancing smart power conversion systems.