A novel control strategy to suppress DC current injection of single-phase PV inverter to the grid

PV inverters without the isolation transformer become more attractive due to higher efficiency and lower weight. However, it may exist DC offset current problem and is critical to power system. In this paper a novel control strategy to suppress DC current injection of PV inverter to the grid is investigated. It is based on idea of accurately sensing the DC offset voltage of PV inverter. Since DC component of the inverter output can be eliminated, DC injection to the grid can be effectively suppressed. Finally the control scheme is verified by the experiment.