A New Grid Synchronization Scheme for a Three Phase PV system employing Kalman Filtering

Abstract

In this work, a new grid synchronization control strategy is developed for a single stage three phase grid coupled Photovoltaic system that employs Kalman Filter Algorithm (KF) to estimate the fundamental sinusoidal components of the Point of common connection (PCC) voltage and load current respectively. The DC-link bus capacitor voltage is regulated employing a Proportional-Integral (PI) controller. KF effectively extracts the fundamental components by updating the Kalman gain such that it minimizes the estimation error variances. Simulation and experimental studies of the proposed KF-PI control strategy shows that it effectively extracts maximum PV power and mitigates load current harmonics reducing the Total Harmonic Distortion (THD) of the grid current and PCC voltage to a lower value which are within the limits presented by the IEEE 519 standards even distorted grid voltage condition.