Advanced control approach for shunt active power filter interfacing wind- solar hybrid renewable system to distribution grid

Abstract

Renewable energy systems utilize the locally available energy resources and generate green energy to meet the increasing load demand. Grid integration of renewable energy systems using power electronic interfaces is the latest trend in this area of research. The non-linear loads at load centers inject current harmonics to the distribution grid at the point of common coupling and pollute the grid. The mitigation of current harmonics in the distribution grid along with the integration of renewable energy systems to the grid is the main focus of discussion in this paper. The interconnection of a hybrid solar-wind renewable energy system with the grid at the distribution level, using a voltage source inverter is presented in this paper. The inverter is controlled using the synchronous reference frame theory based control algorithm, by which the grid interfacing inverter gets additional responsibilities of shunt active power filter. Grid interfacing system consists of a 3-phase, 4-leg voltage source inverter, a dc-link capacitor and a hysteresis current controller. A self-tuning filter is designed and used in the control system for effective elimination of current harmonics. Simulation results are presented with variation in the renewable energy generation and variation in load for validating the practical application of the proposed system. All simulations are done in MATLAB-Simulink platform. The performance of 4-leg inverter in exchanging real power from renewable sources to grid along with compensating current harmonics, under balanced and unbalanced grid voltage conditions are analyzed. JES 2018.