Asymmetric Phase Shift Control in Multiphase Dual Active Bridge DC/DC Converters

Dual active bridge (DAB) dc/dc converter has been widely used to interface the energy storage and dc bus in the application of microgrid with hydrogen or batteries as energy storage systems. Multiphase converter with several DAB in parallel connection can effectively increase the system power handling capacity and realize the ripple cancellation. Conventional symmetric phase shift control cannot guarantee the optimized ripple cancellation under all operating scenarios. An asymmetric interleaving control strategy based on harmonic elimination is proposed to reduce the input current ripple of DAB multiphase converters. Through the optimized control of each single module, full power range soft switching and current root mean square (RMS) reduction can be achieved as well. The mathematical equations to calculate the optimized asymmetric phase shift angles are also derived. Simulation and experiments are conducted to compare conventional symmetric phase shift control and proposed asymmetric phase shift control. Better input current ripple attenuations for the proposed asymmetric phase shift control have been verified with experimental results.