In-Situ Measurement and Investigation of Winding Loss in High-Frequency Cored Transformers Under Large-Signal Condition

This paper presents an in-situ measurement method to accurately characterize the winding loss in high-frequency (HF) transformers, which is challenging to quantify in power electronics applications. This approach adapts the reactive voltage cancellation concept to measure the complete winding loss in HF transformers with the presence of the magnetic core and the load on the secondary side, while this concept was originally brought up for core loss measurement. As an in-situ method, the proposed testing method can factor in the non-linear winding loss elements impacted by the magnetic field interaction between the windings and the core under the large-signal operation, which are not properly assessed in existing approaches. The presented method significantly reduces the sensitivity of the measurement errors linked to the probe phase discrepancy, since the resistive winding loss is well separated out from the core loss. The acquired experimental results are compared and verified with other common empirical measurement methods and three-dimensional (3D) finite element analysis (FEA). As the finding, the measured winding AC resistance is found to be correlated with the load level. Furthermore, treating the complex winding loss and core loss as a black-box problem, this paper proposes a “total loss map” as an engineering solution to practically distribute the measured loss data of magnetic components to the end-users to enable quick and accurate loss estimation/modelling.