A Decentralized Control Scheme for Grid-tied Cascaded-Type PV Inverter Systems

• Published in: IEEE journal of emerging and selected topics in industrial electronics (Print) Vol. 6; no. 1; pp. 184 - 195
• Main Authors: Li, Lang, Sun, Yao, Hou, Xiaochao, Fu, Siqi, Su, Mei
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2025; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Capacitors; Cascaded-type photovoltaic (PV) inverter; Control methods; Control stability; Control systems; Current sources; Decentralized control; Electric potential; Frequency synchronization; Frequency variation; Hardware-in-the-loop simulation; Inverters; maximum power point tracking (MPPT)-based control; Maximum power tracking; Photovoltaic cells; Photovoltaic systems; Power transmission lines; Reactive power; Root locus; Voltage; Voltage control
• ISSN: 2687-9735; 2687-9743
• DOI: 10.1109/JESTIE.2024.3402052

This article proposes a decentralized control strategy for single-phase cascaded-type photovoltaic (PV) inverter systems operating in grid-tied mode. In the proposed scheme, one PV unit functions as a controlled current source, while the others act as voltage sources. Decentralized frequency synchronization is achieved, which is conducive to enhancing the system's reliability compared with the communication-based methods. In addition, the active power outputs for each PV unit, based on maximum power point tracking, are obtained. The proposed method exhibits a robust anti-disturbance capability, particularly under conditions of grid voltage amplitude and frequency variations. Furthermore, the stability of the proposed control is validated using the root locus method for grid-tied cascaded-type PV inverter systems. Finally, the performance and feasibility of the proposed decentralized control method have been validated by simulation and hardware-in-the-loop results.