Grey Wolf Optimization based Power Management Strategy for Battery Storage of DFIG-WECS in Standalone Operating Mode

This paper presents a novel grey wolf optimization based automatic power management strategy of a doubly fed induction generator (DFIG) - wind energy conversion system (WECS) operating in standalone mode. In isolated wind power generation system, either the dc-link or the ac load terminal is backed up by energy storage units, such as battery, super capacitor, dc power supply etc. In such cases, efficient power exchange from the supporting power source is very crucial during load fluctuation and intermittent wind speed. In this paper, a unique meta-heuristic algorithm known as grey wolf optimization (GWO) is introduced to ensure the optimized power exchange in a battery supported DFIG operating in standalone (SA) mode. The proposed optimization algorithm is chosen for its simplistic implementation, fast convergence and superior ability to avoid local optima over other conventional optimization techniques. The reference battery power is generated by the designed control unit which regulates the power flow in optimized manner through the bidirectional converter at battery end. Besides, the load-side and rotor-side converter control blocks are designed to stabilize the generated output. The simulation results of the overall system shows rigorous control over output voltage and load frequency under fluctuating wind speed and variable load condition and efficient battery power flow in standalone operating mode.