A Reduced Stage Dual Active Bridge based Multiport Converter and its Control Strategy

A three port solar PV (SPV) and battery energy storage (BES) integrated grid connected multiport converter (MPC) is proposed in this paper. Dual active bridge (DAB) based high frequency dc-dc stage is utilized to obtain isolation and high dc gain which also increases overall power density of the converter. The novelty of the proposed work is to realize a power circuit configuration and suitable control strategy of a three port converter with reduced stages in the power circuit without compromising its various features. The dedicated boost stage associated with SPV in a conventional MPC is removed in the proposed MPC and the control of SPV is realized through the converter associated with BES and DAB. The other major features of the proposed converter are as follows: all the ports can exchange power seamlessly among themselves, the ac port can be operated in grid connected mode as well as in standalone mode, SPV can be operated both at MPP and non-MPP mode, provision of battery charging from the ac grid, etc. The power circuit topology and the control strategy of the proposed converter is explained in details showing its various modes of operation. A detailed simulation study of the proposed converter has been carried out through a 5 kW three port converter by using MATLAB-SIMULINK platform.