Suppressing method for photovoltaic power station DC component injection

With the large-scale development and application of photovoltaic power, direct current (DC) injection in photovoltaic(PV) power generation system to public power grid is drawing more and more attention. A new method to suppress the DC injection in grid connected PV system is presented in this paper. With the combination of new detection circuit topology and power amplifying circuit topology, the goal of accurately detecting DC component can be achieved. The DC component is superimposed as the modulated feedback signal to the inverter sine wave, through the outer loop voltage control of inverter closed-loop control, the DC component of photovoltaic power generation system can be finally eliminated. The rationality and feasibility of the scheme has been confirmed by simulations and experiments.