Ultra Capacitor Based Sensorless Current Control of Grid Connected Inverter for Power Quality Improvement

Abstract

The economical and environmental impacts of fossil fuels have forced governments and society to investigate sustainable solutions. The interest has focused principally on the green and clean benefits provided by renewable energy sources. The growth rate of new renewable energy supplies being installed has reached the incredible yearly mark of approximately 30% over the last few years. Consequently, investments in research and development in the field of power electronics have increased proportionally, especially in high voltage and high power grid connected systems. This paper presents ultra capacitor based sensorless current control of a three- phase inverter-based distributed generation system. a robust control scheme for high power quality grid connection of inductor-capacitor-inductor (LCL)-filtered distributed generation (DG) inverters. This paper also presents a modified adaptive Kalman filter for sensorless current control of a three-phase inverter-based distributed generation system. The control variable states can be estimated one sample in advance with a reduced number of sensors. Two current control loops with the steepest descent adaptive control for grid voltage estimation have been employed to boost robustness. Stability and dynamic performance have been examined. Simulation and results validate the proposed control approach. Simulation is done using Matlab software.