Small-signal stability analysis of parallel-connected inverters based on time-varying phasor

The droop method has been widely used in the parallel operation of inverters. The coefficients of the droop controller influence the transient response and stability of the wireless paralleled inverters system. However, the conventional phasor representation of sinusoidal signals is constrained by the quasi-stationary assumption, which is generally acceptable for the steady-state or slow-acting analysis. Whatever, this paper presents a small-signal model based on time-varying phasor for parallel connected inverters. Compared with the conventional model, the proposed model can reflect the transient characteristics with more details for the paralleled inverters. Thus, more accurate range for the selection of the droop controller parameters can also be obtained. Simulation and experimental results show validity of the proposed model.