ℓp-Norm Proportionate Based Approach with Mode Transition between Grid Interactive and Standalone of Solar- BES Three Phase Four Wire Microgrid

This paper presents an autonomous 3-phase 4-wire solar PV (Photovoltaic)-battery energy storage (BES) based microgrid controlled through ℓp-norm proportionate-normalized least mean square (LP-PNLMS) current control and mode transition approach. The reliability of the supply across household nonlinear load is enhanced through smooth transfer from grid interactive mode and standalone mode and vice-versa. The solar PV array is equipped with the power optimizer for improved utilization. The LP-PNLMS control is tuned to mitigate the DC offset error, harmonics current, neutral current and to supply mixed (single and three phase) loads on a 3-phase 4-wire wire microgrid. The ℓp-norm factor optimizes the step size to improve the convergence time and to minimize the steady state error in the extracted signal of load current. The islanding/synchronization is detected as per the IEEE 1547-2018 revised standard by estimating the rate of change of positive sequence grid voltages (ROCOPSV), rate of change of frequency (ROCOF) and rate of change of error between the phase angles (ROCOPA). These parameters are estimated by utilizing an improved phase locked loop (PLL) at adverse grid scenarios. The microgrid is modelled in MATLAB and its behavior is analyzed under various operating scenarios e.g. outage/ restoration of grid power, varying nonlinear load, and outage of solar power.