Impact of Interface Controls on the Steady-State Stability of Inverter-Based Distributed Generators

This paper presents a study about the impact of different inverter interface controls on the steady-state stability of inverter-based distributed generators (DG) in the presence of positive feedback anti-islanding schemes. The impact of the constant power controller and the constant current controller on the DG system steady-state stability is compared. The Sandia frequency shift (SFS) anti-islanding control is included in the inverter controllers. The comparison results show that in grid parallel mode the constant current-controlled DG can transfer more power to the connected power system when the local load level is low. However, the constant power-controlled DG has higher power transfer capability for heavy load situations.