Control of multifunctional inverter to improve power quality in grid-tied solar photo voltaic systems.

In this paper, a control algorithm is proposed for a multifunctional inverter to improve power quality in a grid-tied solar photo voltaic (SPV) systems connected to non-linear and unbalanced loads. During light loads and low solar irradiance, the surplus capacity of inverter rating is optimally utilized to compensate some of the power quality (PQ) indices based on conservative power theory (CPT) along with active power injected into the utility grid and also connected loads. The stationary reference frame based proportional resonant (PR) current controller is designed to facilitate accurate tracking of inverter currents, fast time response under dynamic conditions when unbalanced and non-linear loads are connected at the point of common connection (PCC). The proposed control scheme enables selective compensation of power quality indices such as harmonics, unbalance and reactive powers depending on type of load and grid requirements there by, reducing the burden on the utility grid. Experimental results for various dynamic conditions are presented to validate the proposed controller performance and highlight the merits. [ABSTRACT FROM AUTHOR]