Robust Control for PV and Battery DC Microgrid System Based on Passive and Sliding Mode

Abstract

For the photovoltaic (PV) combined battery energy storage systems (BESSs) system, the paper proposed a nonlinear full-order terminal sliding mode (FOTSM) combined with the passive based control (PBC) method. In the PV-BESS DC microgrid system, an Euler-Lagrange (EL) model of the DC-DC bidirectional converter is established first and PBC control is adopted for it. Then adopted FOTSM control laws for the outer-loop instead of traditional PI control. The simulation carried out case studies of changing in light intensity, temperature and load. For the light intensity changed case, compared simulation results depicted that DC-bus voltage can be stabilised within 0.1s under the proposed control, while proportional integral (PI) control cannot meet the control requirements. For the light intensity, temperature and load changed together case, the DC-bus voltage can converge to the given voltage within 0.05 s under FOTSMC-PBC control, with a steady-state fluctuation range of ± 1.5 V. For the BESS, the longest stability recovery time of the current is only 0.073 s, with the fluctuation range of 0.067%. Simulations and experiments have all verified that the proposed method is effective under the different work conditions.