Coordinated Power Control of Photovoltaic-Battery Generation System Based on Self-Synchronizing Voltage Source Inverter

In a photovoltaic-battery (PV-Bat) power generation system, self-synchronizing voltage source inverters (SSVSI) are a promising technology for improving the grid inertia and frequency stability. However, SSVSI's grid frequency support and photovoltaic power fluctuations will lead to system power imbalance. To improve the utilization efficiency of photovoltaic energy and avoid the sharp fluctuation of DC-link voltage caused by the power imbalance, a power coordinated control strategy for the PV-Bat generation system is proposed in this paper. Under the proposed strategy, SSVSI dynamically adjusts the active power command according to the photovoltaic power output to improve photovoltaic energy utilization. Meanwhile, a power feedforward link is introduced into the battery control loop. When the photovoltaic power fluctuates or the grid frequency fluctuates, the battery can quickly suppress the DC-link voltage fluctuation caused by the power imbalance, and significantly improve the dynamic characteristics of battery power regulation. Finally, the effectiveness of the control method is verified by simulation.