Suporte de frequência baseado em Synchronverter aplicado a aerogeradores DFIG

Abstract

This work presents a solution so that DFIG wind turbines can contribute to the primary frequency control in interconnected systems, through a virtual inertia strategy. The proposal consists of modifying the Grid Side Converter - GSC and replacing its control by a Synchronverter, wich is an inverter that mimic synchronous generators to provide synthetic inertia in electric power systems, in addition to including a bank of batteries in parallel with the direct current link of the back-to-back converter to deliver additional power with greater duration and magnitude compared to other technologies. A detailed study of the dynamic models of the machine in state spaces was carried out in the GSC-Synchronverter, which was modified with the inclusion of a virtual resistor in the converter control to improve the stability of the set. The nonlinear models were reduced to the study of small signals and their oscillatory stability and sensitivity were evaluated by the root locus method and implemented in a MATLAB environment. GSC-Synchronverter was evaluated through simulations in PSCAD/EMTDC, in a modified IEEE 14-bus system. DFIG was represented by an aggregate model of 165 MW and replaced synchronous machines of the same power. After simulating load step and frequency drop in the interconnected system, the results proved the effectiveness of the proposal, with the improvement of primary frequency support compared to traditional methods of virtual inertia.