An Energy-Based Control Strategy for Battery Energy Storage Systems: A Case Study on Microgrid Applications

Battery energy storage systems (BESSs) with proportional-integral (PI) control methods have been widely studied in microgrids (MGs). However, the performance of PI control methods might be unsatisfactory for BESSs due to the nonlinear characteristics of the system. To overcome this problem, an energy-based (EB) control method is applied to control the converter of a BESS in this study. The EB method is a robust nonlinear control method based on passivity theory with good performance in both transient and steady states. The detailed design process of the EB method in the BESS by adopting an interconnection and damping assignment (IDA) strategy is described. The design process comprises three steps: the construction of the port-controlled Hamiltonian model, the determination of the equilibrium point and the solution of the undetermined matrix. In addition, integral action is combined to eliminate the steady state error generated by the model mismatch. To establish the correctness and validity of the proposed method, we implement several case simulation studies based on a test MG system and compare the control performance of the EB and PI methods carefully. The case simulation results demonstrate that the EB method has better tracking and anti-disturbance performance compared with the classic PI method. Moreover, the proposed EB method shows stronger robustness to the uncertainty of system parameters