Passivity Control in Modular Battery Energy Storage Systems

This paper proposes a multi-input linear control law based on the incremental passivity theory for cascaded H-bridge (CHB)-based battery energy storage systems (BESSs). The proposed control law guarantees large-signal stability and controls multiple state variables without assuming dynamic decoupling between the voltages and the currents. Assuming dynamic decoupling is generally not acceptable in low-capacitance converters. Furthermore, the broad range of operating conditions in a CHB-based BESS due to the varying state of the batteries and varying grid requirements, makes it important to consider the nonlinear nature of the system. This paper presents a passivity-based control that ensures the global stability despite changing operating conditions. Simulation results on a single-phase CHB-based BESS are shown to corroborate that the proposed control approach exhibits excellent performance.