Power quality enhancement and improved dynamics of a grid tied PV system using equilibrium optimization control based regulation of DC bus voltage

This paper demonstrates the mitigation of current related power quality issues at the distribution end with a gridtied PV system. The power quality problems at the distribution end result from the rapidly increasing non-linearity of the loads. The DC bus stability is ensured by an equilibrium optimized (EO) PI controller, which minimizes the DC bus voltage variations during dynamic conditions, i.e., irregular PV power generation due to insolation variation, grid voltage sag/swell, load, and grid voltage unbalancing. The EO-DC bus control delivers an accurate loss component of current that further enhances the operational capability of the controlled voltage source converter. The EO-DC bus stability is superior to various mete-heuristic optimization techniques, i.e., salp swarm optimization, particle swarm optimization, and genetic algorithm. The suggested block sparse maximum correntropy criteria (BSMCC) based estimation of load current component with l1,0 norm regularized cost function offers improved filtering accuracy against nonlinear load current. The system control executes multiple functions, i.e., power factor correction, harmonics elimination, active and reactive power control, load balancing, and grid currents balancing at the point of common coupling. The BSMCC control outperforms its counterparts, i.e., least mean square, least mean fourth, maximum correntropy criteria, etc. The EO-BSMCC control offers better extraction of fundamental load current components and harmonics elimination during steady-state and dynamic conditions. The EO-BSMCC controlled grid integrated PV system performs satisfactorily as per IEEE 1547 standard.