Control strategies for single-phase grid integration of small-scale renewable energy sources: A review

Small-scale renewable energy sources, such as small hydro turbines, roof-mounted photovoltaic and wind generation systems, and commercially available fuel cells are usually connected to the single-phase distribution grid through a voltage source converter. To regulate the power exchange with the single-phase grid, and at the same time, reduce the harmonic distortions in the ac current, different current control structures have already been proposed, among which the current hysteresis control, the voltage oriented control, and the proportional-resonant based control have found more attentions. This paper provides an overview of the main characteristics of these control strategies. Also, some implementation aspects such as the fictitious signal generation and the single-phase grid synchronization techniques are discussed. Finally, through extensive simulations a comparative study of the presented control strategies is presented. The simulations are supported by experiments.