To suppress wideband oscillations in photovoltaic (PV) power generation systems under weak grid conditions

this paper proposes a control parameter optimization method for grid connected inverters.First

the positive and negative sequence impedance models are established by analyzing the operating characteristics of the PV system.Se cond

a multi frequency finite difference method is applied to perform sensitivity analysis

which quantifies the global impact of current loop control parameters on the system output impedance and identifies their optimization priorities and feasible ranges.Finally

based on the sensitivity results

the whale migration algorithm (WMA) is employed to optimize current loop gain parameters.By balancing exploration exploitation

the algorithm avoids local optima and achieves efficient convergence.Simulation results show that

compared with the unoptimized case

the minimum Euclidean distance of the positive and negative sequence Nyquist curves to point (-1

j0) increases by 0.94 and 0.96

respectively

while the phase margins in the Bode plots improve by 58.098 5° and 68.631 4°

respectively.