Aumento da eficiência do controle do fluxo de potência de sistemas de geração distribuída utilizando impedância virtual implementada por controle de estrutura variável

Abstract

The advances in power electronics and environment restrictions have driven the insertion of renewable energy based systems on the power grid. Generally, these generation systems use the solar and/or wind energy as primary source and they are connected to the power grid through power electronics converters. The integration of these systems into the power grid can produce instability of the electric power system because they are non-dispatchable sources of energy. Therefore, control strategies can be used to ensure the proper functioning of the system. Among the employed strategies, the use of virtual impedance technique has shown increasing interest, allowing to modify the dynamic behavior of the generation unity to improve the transfer of energy to the grid. Currently, the virtual impedance implementation can be used in several applications, such as: power flow control, harmonic and unbalance compensation, active stabilization, among others. This master thesis proposes a virtual impedance technique implemented in a standard three-phase photovoltaic system connected to the power grid in order to regulate its power flow and ensure the stability of the electrical system.