Kalman Filtering Technique for Rooftop-PV System Under Abnormal Grid Conditions

This paper presents a robust extended complex Kalman filter based control for multifunctional double stage grid-connected solar photovoltaic array (SPVA) system. The main contributions this paper, include the following: first, real power generation from SPVA fulfills the requirement of the connected loads and it provides the surplus power to the distribution network, second, it behaves as a distribution static compensator, which performs various functionalities, such as grid currents balancing, harmonics mitigation, unity power factor operation, finally, it is capable to operate under polluted grid scenarios, such as undervoltage, overvoltage, and imbalanced grid voltages. The SPVA feed-forward term is incorporated in the control technique to enhance the dynamic response of the system. The real coded particle swarm optimization based metaheuristic approach is used for optimal tuning of the dc link voltage proportional integral controller. Simulation results illustrate the effectiveness of the presented control algorithm under variations in point of common coupling voltage. Test results illustrate the behavior of the grid-connected SPVA system subjected to various perturbations, such as undervoltages, overvoltages, distorted and imbalanced grid voltages, etc. The total harmonic distortions of grid currents are achieved well within recommended limits.