Sistema de controle para conversores estáticos de energia aplicados em geração híbrida distribuída

Abstract

The distributed generation is a tendency for electric power systems, because it brings a reduction in transmission losses as well expands the possibilities of eletric power supply, strengthening and diversifying the energy matrix. By the normative resolution number 482 of April 17, 2012 , were established general conditions for distributed micro-generation and minigeneration access to the national system, allowing the use of small generators in consumer units which need to keep the voltage, frequency and phase sync at appropriate levels. This work focuses on the control of a DC-AC monophase static power converter which is connected to the grid and loads next to the connection point. This static converter is included in a system that allows the use of hybrid power sources, through sharing the DC bus, such as solar and wind alternatives sources. The topology adopted in this work also enables the application in distributed generation systems such as those cited by the rule. This paper makes a number of computational studies in open loop, with simulations in the software PSIM, changing quantities and parameters of the electrical circuit, which reveal some system features like dynamics obtained from the power grid connection and the need for a phase and amplitude controller. Another need that has been disclosed is a reference generator, which makes possible to use an active and reactive power reference for generating a current reference synchronized by a PLL resonance . For the control of this system will be used control loops in the αβ frame excluding the need for transformation to the dq frame. For the phase sync is used a resonant PLL and in the current loop will be used a resonant proportional controller both of which operate in the aforementioned references. Another advantage worth to be mentioned with the use of the resonant proportional controller is the possibility of a selectively harmonic compensation with a further control loop for each harmonic. Satisfactory results were obtained using this control system in a weak network resulting in a fast phase sync and a good current control being expected as good results when replicating this system to a strong network.