The double-line frequency ripple power exists inherently in single-phase power converters. To address this problem, active power decoupling technique (APD) is widely used. It diverts the ripple power into a small energy storage element through introducing passive and active power devices. This inevitably involves more voltage and current sensors for corresponding control, which raises the cost while decreasing reliability and power density. In this paper, a Lyapunov-based methodology is proposed to achieve APD control without adding any sensor. According to the designed controller laws, the practical decoupling capacitor voltage will converge to its reference. The decoupling voltage reference is given by taking into account buffering the double-line frequency ripple power. Afterwards, the robustness against parameter perturbations of the proposed method is discussed. Finally, the experimental results verify the feasibility of the proposed control strategy.