Off-grid Power Coordination Control Strategy of Parallel Single-phase PV-storage Integrated Converter

Virtual Synchronous Generator (VSG) are used in parallel Photovoltaic-Storage Integrated Converters (PVSIC), aiming at AC power distribution with predetermined proportions and simultaneously enhancing system inertia and damping. However, it does not take into account the variations in DC power, which may result in a suboptimal utilization of PV power. To address this issue, an off-grid power coordination control strategy is proposed in this paper. This method categorizes the DC bus voltage into three distinct levels, facilitating the seamless transition of control among the battery DC/DC converters, DC/AC converters, and PV DC/DC converters. In this method, the DC Bus Voltage Clamp (DBVC) control is integrated into the VSG control curve of DC/AC side. The residual power generated by the PV in one PVSIC is subsequently directed to other PVSIC. Concurrently, a DBVC operating at a higher voltage level is incorporated into the DC/DC control on the PV side to decrease the input power from the PV arrays automatically when the residual power generated by some PVSICs cannot be utilized by other PVSICs. Thus, the proposed method can ensure the comprehensive utilization of energy from each PVSIC. Finally, the efficacy of the proposed method is validated through simulation results.