With the increase in the penetration level of distributed energy resources, the voltage and frequency instability of the grid becomes a significant challenge. The Virtual Oscillator Control (VOC) is a grid-forming method with fast response speed and a unique self-synchronization mechanism, which can provide voltage and frequency support to the grid. However, at the grid-connected power output side of the inverter, the coupling between active and reactive power leads to steady-state errors and dynamic power oscillations, which limits the power output capability of the grid-connected inverter. Therefore, a power decoupling control strategy for VOC controlled inverters is proposed in this paper. Firstly, a small-signal model for the VOC inverters' power coupling is established, and the mechanism of power coupling is investigated. Secondly, the reason for the decoupling capability limitation is revealed based on the virtual impedance method. Then, an impedance and voltage compensation method by reducing the power angle is proposed to achieve power decoupling for inverters. Finally, the effectiveness of the impedance and voltage compensation strategy is validated through MATLAB/Simulink and OPAL-RT OP5600.