Modulation Strategy to Minimise RMS and Peak Currents in Dual Active Bridge Converter

Abstract

Optimal operation of dual active bridge (DAB) converters has been extensively researched in literature. The modulation parameters of the DAB converter are chosen to minimise a given objective function which can be the RMS or the peak of inductor current. This paper presents a comparison of the optimal rms current problem and the optimal peak current problem. For medium power operation, a closed-form solution is derived for the modulation parameters which leads to minimum RMS currents. It is observed that the solution is computationally demanding and hence not suitable for real-time implementation. A hybrid modulation strategy is proposed which achieves both optimal rms and peak currents and is simple to implement in real-time. Simulation and experimental results confirm the theoretical analysis.