In this paper, a new control method is proposed for the DC/DC boost converter of the grid-connected renewable power generation system. The proposed control method can suppress the ripple voltage with double fundamental frequency of the utility superimposed on the output voltage of renewable energy source. Hence, the power efficiency of the renewable power generation system is increased. Only a voltage detector detecting the output voltage of DC/DC boost converter is used in the proposed control method, so that the control circuit is simplified evidently. Experimental results of the developed prototype show that the performance of the proposed method is as expected.