Performance Evaluation of Mode Transition Strategy for 3P4W Microgrid Utilizing SOAP-FLL and LMLS Filtering Approach

This work focusses on the performance evaluation of a three phase four wire (3P4W) AC microgrid under mode transition. The changeover from utility integrated to standalone control is carried out using modified synchronous observer aided preprocessing based frequency locked loop filter (SOAPFLL). It effectively traces the grid and load angle utilized for synchronization purpose. The power generation units of wind and PV power are the renewable resources utilized to fulfill the critical load demand under grid outage mode. The battery associated with bidirectional DC-DC converter allows reduction in the battery capacity rating. In fact, effective load current fundamental constituent extraction is carried out using least mean logarithmic square (LMLS) algorithm. It reduces the effect of the non-linear load harmonics on the utility power quality. It also allows sensitive load operation at the point of common coupling (PCC). The microgrid is modelled in Matlab and the simulation result procured, depict the smooth mode transition from utility associated operating mode to utility outage mode and vice-versa. The harmonics appearing in the grid current are eliminated successfully while providing enhanced power quality of grid and voltage of PCC.