Design and Implementation of Load Network Time Constant Computation Based Solar Active Power Filters Cum Injector for Industrial Loads/Grids

This work proposes an efficient integration method of solar energy with industrial nonlinear loads, accounting for dynamic variations in solar power and load harmonic profiles. The involved dynamics necessitate that the solar interface front-end inverters be equipped to handle both harmonic distortions and active power injection characteristics simultaneously. In this work, an instantaneous load and source characteristic mapping is proposed for the solar-interfaced front-end inverter operated as a shunt active power filter cum active power injector in order to accommodate the dynamic variations of the source and load. As per requirement, to separate the load-demanded and switching harmonics, a new load network time constant-based passive filter design diverging from traditional passive filter design methods is demonstrated. Further, a comprehensive explanation of the current controller modeling methodology is elaborated, considering the essential bandwidth required for proficiently managing load-demanded harmonics in both grid injection and drawing modes of operation. Later, in grid injection mode, the influence of grid and system impedance interactions on the power quality is analyzed for weak grid scenarios to derive the requisite bandwidth conditions to ensure resilient power transfer. Subsequently, the experimental validation of the solar interfaced shunt active power filter (SISAPF) with active power injection capability is carried out in both grid power drawing and injection modes, demonstrating the effectiveness of the enhanced bandwidth in handling load-demanded harmonics and solar power dynamic variations.