Sliding mode vector control of grid-connected PV multilevel systems based on triple three-phase two-level inverters

The use of distributed architectures for PV panels present several advantages over centralized solutions, such as better harnessing of the generated energy and improved reliability of the system. Therefore, several inverter structures have been proposed to ensure proper operation of distributed architectures and at the same time generate multilevel voltages. A newly proposed structure uses three three-phase two-level inverters. Thus, in this paper a new control system is proposed for grid-connected PV systems with this structure. The proposed control system is based on a sliding mode AC current controller that uses space-vector voltage modulators. The proposed control system is also designed to inject unbalanced power into the grid to provide an ancillary service regarding power unbalances. The proposed controller for the mentioned structure is then tested through several simulations considering different case studies.