Medium Frequency Transformer Leakage Inductance Modeling and Experimental Verification

This paper provides detailed analytical modelling and finite elements method (FEM) analysis of the medium frequency transformer (MFT) leakage inductance, as one of the key design factors governing the operation of galvanically isolated power electronics converters. Precise leakage inductance modeling in design stage is especially important for converter topologies based on resonant conversion where MFT is a part of a resonant circuit. A comprehensive analytical model that takes into account both the geometric and frequency effects on the given MFT leakage inductance is generated based on the transformer physical structure, thus allowing for optimisation of the MFT design with targeted equivalent circuit leakage inductance reference. The derived models are benchmarked to the measurement results on the developed MFT prototype

Novel Insight into the Output Current Ripple for Multilevel and Multiphase Converter Topologies

When it comes to the computation / estimation of the switching losses in a multilevel converter, it is crucial to know the instantaneous value of the output current. If the average output current value is used instead, there is a non negligible error when the quality of the output current waveform is low. This paper addresses this issue with a generic and versatile fast numerical method for phase-disposition PWM that produces the exact switching pattern, hence the exact inductor flux, without having to run time-domain switched simulation(s), as the calculations are performed for the minimal set of points required to fully determine the inductor flux ripple at the switching instants