Dual Active Bridge Converter Control and Power Management of PV-Battery fed DC Microgrid for EV Battery Charging System

In this paper, the design, control and power management of a dual active bridge (DAB) converter for an electric vehicle (EV) battery charging system is presented. The DAB topology is widely used in EV battery charging and DC microgrid (DCMG) applications due to its bidirectional power flow potentiality, galvanised isolation and implicit zero voltage switching (ZVS) characteristics. A PV-battery fed DCMG is designed with a SEPIC converter for PV system and a non-isolated bidirectional converter (BDC) with suitable controller for charging/discharging of the storage battery to maintain a constant DC bus voltage. The DAB converter is interfaced with the designed DCMG using an extended phase shift (EPS) modulation scheme for transferring power with zero back power flow to the EV battery. The simulation results of DAB converter along with power management and DC bus voltage regulation of DCMG are showcased for 1.5 kW, 96 V/48 V EV battery charging in buck mode operation. This developed system can be further explored by operating the DAB in closed loop for bidirectional power flow with ZVS switching in grid to vehicle (G2V) and vehicle to grid (V2G) modes.