Single-phase ZVS AC-link inverter for PV-grid connection at MPPT operation

This paper presents a single-phase zero-voltage switching (ZVS) AC-link inverter for PV-grid connection at maximum power operation. The PV modules charge an AC-link until it reaches a certain reference current waveform; while, in the same time, the PV modules is connected to the grid inverter via a series inductor. Then the PV modules are disconnected and the charged AC-link discharges into the grid. The proposed controller employs a conventional MPPT to maximize the PV output power. Then the controller generates the link´s reference current to fulfill both of MPPT and the desired active/reactive power needs to be injected into the grid. The proposed topology along with the proposed controlling strategy achieves a flexible and continuous power flow features. A detailed descriptive figure of the inverter´s operating modes and their switching strategy is presented in this manuscript. Furthermore, a simulation model is developed in MATLAB/Simulink environment for the overall system and the results are addressed. Results show that the proposed AC-link inverter successfully achieves PV-grid integration at good dynamic and steady-state performances.