DSOGI-PLL Based Solar Grid Interfaced System for Alleviating Power Quality Problems

In this paper, a DSOGI-PLL (Dual Second Order Generalized Integrator Phase Locked Loop) based control approach is proposed for single stage, 3P3W (Three Phase Three Wire) solar-grid interfaced system with distribution static compensator abilities. This DSOGI algorithm helps to attenuate current/voltage harmonics and to estimate symmetrical components of current/voltage rapidly under unbalanced grid conditions. These sequence components elicit the fundamental component in load currents. An incremental conductance (INC) based technique serves the MPPT (Maximum Power Point Tracking). The proposed system is simulated in MATLAB/Simulink environment. A prototype is developed and tested for various loads in the laboratory. Test results obtained, validate the control approach of proposed system under steady state as well as dynamic conditions such as unbalance in load and change of solar insolation level. The important parameters as the total harmonic distortion (THD) and the percentage of unbalance of voltage and current phasors are noted and found to be satisfactory as per the IEEE-519 standard.