Power Sharing Controller for Modular Dual Active Bridge DC/DC Converter in Medium Voltage DC Applications

This paper presents a new structure of a power sharing controller for a modular based dual active bridge (DAB) DC/DC converter. The modular topology is based on input-series output-parallel (ISOP) connection of DAB modules suitable for a voltage step down application at medium voltage level. Since DAB has bi-directional power flow capability, this connection would act as its dual input-parallel output-series (IPOS) counterpart in the case of reverse power flow. The proposed power sharing controller ensures uniform power sharing among the modules even in the case of parameter mismatches as well as manages converter operation during pole-to-pole and individual module DC faults. Results for the proposed controller are justified using a detailed Matlab simulation model.