Grid-connected inverters play a crucial role in renewable energy power systems. As the penetration of renewable energy sources increases, the dynamic interaction between inverters and the grid leads to complex oscillation issues. This paper addresses the low-frequency oscillation problem by proposing an impedance shaping method based on voltage feedforward. The impact mechanism of the Phase-Locked Loop (PLL) on system stability and the influence of PLL control bandwidth on system stability are analyzed. By employing the impedance shaping method, the system’s low-frequency impedance characteristics are reshaped to enhance stability during impedance interactions. The stability of the system is further analyzed through positive and negative sequence equivalent impedance models. Finally, the proposed impedance shaping method is validated through hardware-in-the-loop (HIL) simulations, demonstrating its effectiveness in suppressing low-frequency oscillations.