Virtual Oscillator Control of Series-Connected PV Powered Converters for MV Grid Integration

Cascaded converters are used to achieve higher ac voltages with low-voltage semiconductor devices. The focus is on localized power transfer between low-voltage solar photovoltaic (PV) systems dispersed across converter dc links, with the converter ac sides being series-connected to a three-phase medium-voltage ac grid. Currently, decentralized controllers that enable power transfer in these systems are limited. To address this need, a virtual oscillator (VO) controller based on an Andronov-hopf oscillator (AHO) is proposed, enabling decentralized power transfer and utilizing only locally measured current. The approach allows for communication-free synchronization of the converter modules and does not require phase-locked loops. Since the VO control uses a time-domain implementation, it achieves superior transient response. The simulation results show the controller’s fast response, grid synchronization, and effective power dispatch based on the PV power variations.