Variable frequency control strategy for transformers surge current reduction in DAB converters

The reliable operation of Dual Active Bridge (DAB) converters can be greatly improved by reducing the overshoot in the transformer current. A new variable frequency control to effectively mitigate this transient overshoot is presented in this article. The proposed technique is designed to require minimal processing capacity, as well as compatibility with most of the DAB modulation techniques. The performance of this technique is analyzed using MATLAB/Simulink and PLECS. Experimental results are obtained on a DAB converter based on GaN e-HEMTs. These results show how the proposed technique considerably subdues overshoot in the transformer current and consequently reduces thermal stress and potential failures in the power semiconductor devices.