Stability analysis of single-phase grid-connected inverter with L-filter

As an important part of the distributed power generation system, grid-connected inverter has been widely used. However, as a time-varying nonlinear system, the grid-connected inverter has complex dynamic behavior, which can cause serious stability problem. As a consequence, more and more researches have focused on this issue, most of which are limited to the stability problem caused by the variations of controller parameters, input voltage or load. This paper analyzes respectively the factors that may lead to instability such as harmonic voltage amplitude, harmonic voltage order, inductor saturation and dead-time nonlinearity. The analysis result shows that the harmonic voltage will not influence the stability of the system, but the inductor saturation and dead-time effect will cause serious stability problem in some cases. Furthermore, the design references of the controller parameters are proposed based on the result of stability analysis, which supplements the existing design references.