Active power quality improvement for unified renewable energy system with multilevel inverter and PEKF controllers

Standalone microgrid with hybrid wind-PV-fuel cell renewable energy resources is necessary to meet the power demand in remote areas where the utility grid is not available. Renewable energy resources are erratic, (i.e.) sudden changes in the climatic condition generates variable output voltage that affects the reliability of the power electronics system providing voltage stress, switching losses and deliver harmonic deviation. Hybrid PV-wind-fuel cell provides multiple conversion stages, which reduces the efficiency of the system. In order to overcome this issue, this paper proposes new dc-dc boost converter for improving voltage gain and a predictive exogenous Kalman filter with fuzzy controller (PEKF) employed with bumble bee selective harmonic elimination-pulse width modulation for reducing the harmonic and maintains the system at steady state and also a cascaded 9-level H-bridge converter is utilized that operates at high voltage with stress per switching at lower voltage, higher efficiency and low electromagnetic interferences. The PEKF controller is utilized to predict the state and to improve power sharing injected by renewable energy resources. To show the effectiveness of the proposed scheme, simulations are done in working platform MATLAB/SIMULINK environment.