A Grid-Tied Reconfigurable Battery Storage System

This paper presents a grid-tied reconfigurable battery storage system, which consists of a single-phase two-stage bidirectional PWM converter and a reconfigurable battery pack (RBP). The two-stage PWM converter provides an interface between the AC power grid and the RBP and operates in two different modes: (1) grid to battery (G2B) mode, in which the RBP is charged from the AC power grid; and (2) battery to grid (B2G) mode, in which the RBP delivers the stored energy to the grid. In the RBP, fault tolerance and state of charge (SOC) equalization among battery cells can be realized by dynamically configuring the connections of battery cells, no additional SOC equalization circuit is required. A laboratory prototype of the proposed battery system was designed and fabricated. Experimental results on the prototype are provided to validate the features of the proposed battery system.