A Reliable Microgrid Comprising Solar PV-WEGS and Battery With Seamless Power Transfer Capability

Abstract

This article implements a new control method for a microgrid configuration comprising wind energy generation system, a solar PV array, a battery, local loads, and the utility grid, which provides a seamless transition of power during on-grid to off-grid operations and vice versa. This microgrid uses synchronous reluctance generator (SynRG) operated by a position (mechanical) sensor-less field-oriented control, for electric power generation from a variable speed wind turbine. The output of the solar PV array is connected to the dc-link of the microgrid through a dc–dc boost converter, whose output voltage is regulated at the desired value by the battery bank. For smooth synchronization and fast dynamic response, a fourth-order generalized integrator-based frequency-locked-loop with pre-filter (C-FGI-FLL) is implemented in this work. The use of C-FGI-FLL enhances the filtering capabilities of FGI-FLL under weak grid conditions, without affecting the computational burden. The C-FGI-FLL generates filtered input and its quadrature component, and these are used for the extraction of positive sequence components of the grid voltages. For faster dynamic response during load variations, C-FGI filters are used in each phase so that fundamental peaks of load currents are extracted accurately without any delay. The accurate and quick performance of this filter makes the system dynamics fast without deteriorating the performance. Simulation and experimental validations of this microgrid have been carried out both for dynamic and steady-state conditions.