Distributed energy storage system‐based nonlinear control strategy for hybrid microgrid power management included wind/PV units in grid‐connected operation

摘要

In this paper, a control strategy based on a combination of Lyapunov theory and input-output feedback linearization (IOFL) has been proposed to provide stable operation for a hybrid DC/AC microgrid under unbalanced generations of the AC units. The DC link of the considered hybrid microgrid was supplied through photovoltaic (PV)-based buck and lithium battery-based (LB-based) bidirectional DC/DC converters. A DC/AC converter was connected to the DC link and set to provide the required active and reactive power for reaching the desired waveforms for the point of common coupling (PCC) voltages. To accurately control the aforementioned converters, the mathematical equations were first achieved and then the proposed IOFL was designed to obtain the control inputs. To enhance the IOFL performance, several control loops regarding DC link voltage variations were considered for all converters. The main contribution of the proposed IOFL is that the control input of the LB-based bidirectional DC/DC converter consists of both control inputs of the DC link-connected inverter. As another contribution of this paper, total energy due to the control inputs' errors was completely investigated through the Lyapunov theory, leading to effective dynamic parts for the control inputs. In addition, the DC and AC power sharing was comprehensively evaluated based on both AC and DC specifications. For further analysis, the effects of angular frequency variations on the inverter control inputs were presented. Simulation results through MATLAB/SIMULINK software verified the accuracy and ability of the proposed control strategy.