Hybrid Current-and Voltage-Mode Control of Grid-Connected Cascaded Inverters

For the power balance control and AC voltage synchronization of the grid-connected cascaded inverters, the existing control methods are implemented with requiring the grid synchronization signals of all inverters. In this paper, a hybrid current-and voltage-mode control scheme is introduced based on only one communication link. Compared to the existing control strategies, the communication link and complexity are greatly reduced, thus it is more reliable and cost-effective. The other potential advantages of the adaptivity under the grid voltage sag and frequency deviation conditions are obtained. Meanwhile, maintaining the AC synchronization and injecting the desired power into the grid are guaranteed. The system stability conditions are derived, and the feasibility of the proposed method is verified by simulation results.