A Self-Synchronized Decentralized Control for Series-Connected H-bridge Rectifiers

This study proposes a decentralized coordination control scheme for series-connected H-bridge rectifiers. Each rectifier module is controlled as a voltage-controlled source by a local controller, which needs only individual information. The local controller is composed of an active power-frequency (P-ω) control and a fixed voltage amplitude control. Compared to the conventional methods based multi-level phase-shifting modulation where centralized controller is needed, the proposed control strategy allows indefinite modular expansion without increasing the computational load of the local controller. Therefore, it has decreased cost and increased scalability. The synchronization mechanism of series modules is analyzed and the stability of the system is proved. The feasibility of the proposed strategy is verified by experimental results.