A coordinated control strategy for standalone DFIG–BES microgrid with energy management and power quality enhancement

As renewable energy sources and nonlinear loads are integrated into microgrids supplying isolated loads, they are becoming increasingly dynamic and challenging to operate. Power quality and stability of isolated microgrids may be adversely affected by nonlinear loads, which introduce reactive power demand, harmonic distortion, and rapid variations in active power. The paper describes a coordinated control framework for a doubly fed induction generator (DFIG)-based microgrid couples with Battery Energy Storage (BES) for reliable and continuous supply to isolated nonlinear loads, maximum power capture and power quality addressal capability. This control framework coordinates the rotor-side converter (RSC), load-side converter (LSC), and bidirectional DC–DC converter. For the RSC, static flux-oriented technique of vector control is used to maximize wind power extraction, while for the LSC, indirect current control based on synchronous reference frame (SRF) adjusts the point of common coupling (PCC) voltage and compensates for the reactive power and harmonic currents drawn due to presence of non-linear loads. By integrating a bidirectional DC–DC converter on the DC side of the microgrid, the BES balances the power mismatch caused by source variations and load fluctuations. While maintaining regulated PCC voltage and frequency, the DFIG and BES maintain continuous power supply to the isolated loads. MATLAB/Simulink 2023a is used to test the performance of the established control strategy pertaining to variable wind generation and non-linear load conditions. Power sharing between the DFIG and BES is effective, power quality is improved, PCC voltage is stable, and harmonic distortion is within the prescribed limits, confirming that the proposed DFIG–BES microgrid is suitable for isolated-load applications.