Predictive Control of Two-Stage Grid-Connected Photovoltaic Energy System with Constant Switching Frequency

In photovoltaic energy systems, a two-stage power conversion system composed of boost converter and three-phase voltage source inverter improves the energy conversion efficiency. A novel deadbeat current control (DBCC) for the boost converter and a modulated model predictive current control (M
²
PCC) for the grid-side converter are proposed to obtain constant switching frequency operation. The DBCC regulates the inductor current for the maximum power point tracking, while the M
²
PCC controls the stationary-frame grid currents such that the grid active and reactive powers are regulated with excellent power quality. The proposed control strategies ensure less steady-state error and fast transient response under a wide dynamic range. To verify the feasibility of the proposed controls, simulation studies are conducted on a 12-kW system at different irradiance, temperature and grid reactive powers.