Experimental Validation of a Control Strategy Enhancing the Dynamic Performance of Current-Fed Triple-Active-Bridge DC-DC Converters

This paper provides the experimental validation of a control strategy that enhances the dynamic performance of current-fed triple-active-brigde (CFTAB) converters to its physical limits. So far, current transients in the inductors of CFTAB converters are often accepted or ignored in the literature, as the considered time interval of simulation and measurement results is typically very large so that the transient behavior of the current is not visible. In this work, a model-based control strategy is examined that reaches the new steady state after a load step as fast as physically possible and furthermore reduces current oscillations, saturation and additional losses. A 1kW GaN-based CFTAB converter prototype is presented and the benefits of the examined control strategy are demonstrated by measurement results. It is shown that the settling time after a load step can be significantly reduced from about a millisecond down to several microseconds.