Passivity-Based Stabilization of LCL-filtered Grid-Connected Inverters with Wide Variant Inductance

The high magnetic permeability of inductors can effectively increase the efficiency and power density of grid-connected inverters (GCIs). However, the high magnetic permeability often results in wide variant inductance, which imposes severe challenges to the stability of GCIs. This paper examines the influence of inductance variation on GCI’s output admittance from the perspective of passivity and presents an optimal design method for controller parameters to ensure that the GCI’s output admittance remains passive while the inductance is reduced to about one-third of the initial value. Finally, the accuracy of the theoretical analysis and the effectiveness of the design are verified by the simulation and experimental results.