A new control approach for islanded microgrid system: Based on correlative techniques

The microgrid frequency and voltage are two important parameters that change with the existing uncertainties in microgrid system in island modes especially. Therefore, these parameters must be controlled so accurately to assure the power quality. This paper proposed a control scheme for frequency and voltage controllers using the power system circuit equations and droop controller. To maintain the voltage near the nominal value, a novel PI controller is added to voltage control path by a switching term in transient states. The PI controller quickly damps the voltage deviation by adding this difference to output voltage amplitude. The profit of this method is the control of both stable and transient states in one design. The simulation results show that the microgrid system outputs track the load changes in transient mode and are set on nominal values.