Islanding Operation and Seamless Resynchronization in DFIG–SPV System Equipped With Functional Enhancements Through ATLLAD Control Framework

Abstract

Doubly-fed induction generator (DFIG) and solar photovoltaic (SPV) array equipped hybrid wind-solar generation system is increasingly acknowledged as a viable techno-economic solution for remote-area electrification. Despite the progress made in this frontier, two major hurdles still persist. The first hurdle relates to the power inadequacy for local loads and the mode transitional features in DFIG-SPV system, during grid outages, which are rather frequent in remote-areas. Another issue in DFIG-SPV system at remote-areas is its functional vulnerability at the irregular grid conditions like unbalance and distorted voltages. Taking these aspects into consideration, this paper implements a new arc-tangent least logarithmic absolute difference (ATLLAD) based control framework for DFIG-SPV system. The operational scheme ensures disruption-free load power at islanding scenarios, while, the control strategy enables seamless transitions without inducing overcurrents or voltage spikes during mode switching. To deal with DFIG-side functional vulnerability at irregular grid conditions, ATLLAD-based control uses an innovative approach to impart an additional degree of freedom for the simultaneous suppression of DFIG torque oscillations and reduction in DFIG stator current disturbances. Meanwhile, the enhancement at the grid-side involves injection of improved quality grid currents despite the irregularities in the grid voltages and the load currents. Test results from an experimental-rig of the DFIG-SPV system illustrate satisfactory performance of ATLLAD control approach.