Coordination Control Strategy of Photovoltaic Energy Storage System Based on DC Voltage Signal

Based on the optical storage system composed of photovoltaic system, energy storage device, grid-connected inverter and AC/DC load, it has researched on the control strategies of run modes including off-grid and grid connection, respectively. Considering the randomness of photovoltaic devices, the charging and discharging properties of energy storage devices and the phenomenon of variable load, the DC side voltage layered control mode was proposed. On the basis of the DC voltage amplitude with coordination of adaptive droop control for energy storage devices, at the same time, the grid-side bidirectional converter adopts virtual synchronous power generation technology so that DC side voltage can be more stable to reduce internal power conflicts and ensure the stability of internal power exchange. Finally, through MATLAB/Simulink being in off/connected mode, the effectiveness of coordinated control strategy was verified separately by simulation. The simulation results show that: in off-grid mode, compared to the droop control, the introduction of virtual synchronization has increased robustness of the system. The coordinated control strategy has ensured the stability of the system and realized the effective utilization of the energy storage device.