A Decentralized Control System for Series-Connected Grid-Integrated Photovoltaic Inverters

This paper introduces a novel decentralized control method designed for series-connected single-phase photovoltaic (PV) inverters. Each PV unit conducts maximum power point tracking (MPPT) independently and synchronizes with the grid autonomously, relying solely on local measurements. In this method, one inverter serves as the current administrator to regulate the grid current, and the remaining inverters operate as voltage administrators. Compared to existing methods, the proposed approach eliminates the need for low-bandwidth communication links for grid voltage measurement and synchronization. Case studies demonstrate the effectiveness of the proposed method across diverse scenarios, including varying PV power generation, grid contingencies, and inverter fault scenarios. This approach reduces the control system cost and complexity, enhances reliability, and facilitates fault tolerance of series-connected PV inverters.