With the fast expansion of inverter-based renewable energy integration, the novel grid synchronization technology, power synchronization control (PSC), has attracted much attention. However, the synchronization characteristics of PSC, e.g., the perturbation suppression ability, synchronization speed, and its relationship with control parameters have not been essentially clarified. In this paper, a detailed phase error model of PSC loop under the perturbation condition has been derived by adapting the harmonic linearization method. Since the impacts of both power calculation and vector current control have been considered, the proposed model could precisely describe the influence of control parameters on the synchronization performance and PSC perturbation suppression ability. Based on this model, a unified system design strategy is presented for simplified multiloop decoupling analysis, by which the synchronization parameter could be determined by a unary formula with iteration and refinement. All theoretical analyses have been verified by simulation and experimental results. The work of this paper might be beneficial for the large-scale integration of inverters.