Weak Grid Interconnection of Solar Photovoltaic Unit with Power Quality Conditioner Functionality

The power electronics driven nonlinear loads exhibit discrete switching characteristic and thus, redundant harmonic components are reflected into the utility grid currents. These current harmonic components cause a nonlinear voltage drop across the grid impedance leading to considerable distortions in the voltage. These harmonic distortions jeopardize the operational performance of adjacent linear loads coupled at the point of connection. Therefore, to remediate the various Power Quality (PQ) issues posed by nonlinear loads, this article proposes an Advanced Shrinkage Normalized Sign (ASNS) based control architecture for Photovoltaic (PV) inverter controlled PQ conditioner. More precisely, the proposed ASNS scheme is intrinsically responsible for decomposing the fundamental weight components of the load currents from harmonically adulterated currents. Besides active power injection into the established grid, ASNS is required to serve the following distinctive control objectives under weak distribution network: (i) Active compensation of nonlinearity introduced by the PV array; (ii) Grid current balancing; (iii) Harmonic and reactive current compensations, and (iv) Power factor correction. Furthermore, all the theoretical developments are examined through numerical simulations in MATLAB/Simulink environment using SimPowerSystems toolbox. In summary, the tests results substantiate the effectiveness of the ASNS architecture to operate seamlessly even under adverse grid scenarios and thereby improving PQ.