A Stability Improvement Method Based on Parameter Sensitivity for Grid-connected Inverter

Due to the fluctuation of the power grid and the use of filters, the grid-connected inverter is prone to oscillation, so it is very important to develop an universal stability-improving method for the grid-connected inverters. The traditional stability improvement methods are mostly based on the frequency-domain transfer functions, and the proposed method has great randomness. In this paper, a stability improvement method based on parameter sensitivity combining time-domain Floquet theory is proposed firstly, which can develop a series stability-improving methods for the grid-connected inverter according to the practical requirements, without deriving the complex input impedance and output impedance of the inverter system. Further, taking a single-phase gird-inverter as an example, the proposed stability-improving method is introduced and verified in simulation. Finally, the correctness and the effectiveness of the proposed method is proved by the simulation results.