Dual Mode Operation of a Switched Reluctance Generator Based Wind Energy Conversion System and a Battery Integrated MG under Abnormal Utility Grid Conditions

Abstract

In this paper, a grid interfaced microgrid (MG) consisting of switched reluctance generator (SRG) based wind energy conversion system (WECS) is presented. The SRG provides an attractive solution for WECS due to its outstanding merits over other conventional generators used in the WECS, such as low cost, rotor free from windings or magnets hence lesser losses, higher efficiency, wide speed operation and no cooling arrangement is required for rotor side. The maximum power from the wind energy is harvested effectively by controlling the asymmetric half-bridge (AHB) SRG converter. Battery storage is provided at the DC bus of the DC-AC power converter to balance the power in the MG. The primary focus is given to the clean wind energy source to meet the load demand. The power generated from the WECS becomes lower/excess than demand, then deficient power is met from the utility grid, or the excess power is injected into the utility grid to balance the power within the MG. Whenever the utility grid fails, then the MG operates in off-grid mode, where the power output from the WECS and the battery storage balances the power within the MG. Moreover, once the grid failure is resolved, the MG is automatically shifted to on-grid mode without causing any disturbances in the MG. An improved second-order generalized integrator-frequency locked loop (ISOGI-FLL) filter is developed to estimate the positive sequence components (PSCs) of the utility grid voltages to enhance grid power quality even under abnormal grid conditions. Moreover, it calculates the load currents active weight fundamental components for enhancing the quality of various power quality (PQ) indices at the utility grid.