Conventional droop method ignores the importance of power measurement for frequency and voltage difference control. Power measurements are usually obtained by first-order low-pass filters. The bandwidth limitation due to the inherent low frequency pole. So there must be a trade-off between a suitable power ripple rejection and response time. In the isolated inverter operating system, the selection of droop parameters has a great influence on the stability and transient response of the system. The traditional quasi-stationary phasor neglects the components of dynamic changes in the system, theoretically stable control parameters may lead to the instability of the actual running system. Based on these, the notch filtering algorithm is introduced to establish the small signal model using time-varying phasor in inductive system, and a more accurate parameter selection range is given, on the basis of analyzing the dynamic process of the system, the reason for the expansion of the stable region in the quasi-static model is explained. The notch filtering algorithm improves the power ripple rejection and system responsiveness. Both simulation and experimental results verify the validity and effectiveness of the proposed method.