First Observations in Degradation Testing of Planar Magnetics

Abstract

Magnetic components are usually assumed relatively reliable in power electronic converters. Nevertheless, with the trend for ever-increasing power density, planar magnetics may need to be designed with reduced margins in terms of thermal and insulation. Wear out or even failure of magnetic components may become an issue in extreme design and operation scenarios. This paper presents the first observations in degradation testing of planar magnetics at high temperatures. It serves to investigate the change of various parameters and identify possible ones as the health indicators of magnetic components for power electronic applications. The degradation testing and characterization results are presented and interpreted.

Power Electronics Reliability: State of the Art and Outlook

“…The reliability aspect studies of medium-frequency to highfrequency magnetic components for power electronic applications are rarely available. The first studies are presented in [51,52] on the degradation testing and lifetime modeling of planar transformers. Two groups of 12 samples are tested under 200°C and 180°C, respectively, for 3,500 hours and 2,500 hours.…”

“…Typically, 6 to 10 samples for each testing run are recommended for a meaningful statistical analysis compromised with the required resources. For instance, 10 and 12 samples are used for capacitor and planar transformer testing in [51], [55], respectively. Nevertheless, it is reported that 86% of the power cycling tests have only one sample per test run based on the 70 publications discussed in [4].…”

“…The understanding of failure mechanisms of magnetic components in power electronic applications is still limited. The early studies presented in [51,52] show the need to further investigate the failure mechanisms and degradation models, especially for planar magnetic components in high-density converters and medium-voltage medium-frequency isolation transformers.…”

Degradation Analysis of Planar Magnetics

“…The planar transformer test setup and the specimen are detailed introduced in [20]. In that work, the core and impedance measurement is with non-negligible errors.…”

“…This paper is a further research of [20] and investigates the failure mechanism and lifetime assessment of planar magnetics. It is with three major contributions:…”