Abstract: In a cascaded system consisting of LC filters and Buck converters with constant loads, improper design of the front-end circuit′s LC filter parameters can lead to voltage oscillations due to parameter mismatches between stages.Although existing research has explored approximate linearization modeling, impedance ratio criteria, and damping control design of the system, they have overlooked the impact of filter losses.So this paper proposes a system circuit model that includes filter loss parameters.Based on this model, small-signal equations are formulated to derive the equivalent impedance of the system port.Subsequently, the Routh-Hurwitz Criterion is applied to analyze the influence of loss parameters on system stability, leading to the design of individual transfer functions for the system′s active damping feedforward control loop.Finally, the effectiveness of this control method is evaluated and validated through impedance ratio criterion, equivalent impedance Bode plots, and simulation results.