Sistema de geração eólica com filtragem de correntes harmônicas

Abstract

Point Tracking (MPPT) technique. The generator is controlled in dq coordinates through the orientation of the rotor’s magnetic flux, using PI controllers for the speed and current loops. The GSC is responsible for regulating the electrical currents delivered to the point of common coupling (PCC) by means of an inductive filter, as well as controlling the electrical voltage of the DC bus. The GSC is controlled in synchronous coordinates, where the DC bus voltage loop uses PI compensators, while the current loops use LQR controllers with integral action. Three active compensation proposals are used to evaluate the performance of the wind system. Proposal 1 is based on the Synchronous Reference Frame (SRF) compensation method for harmonic filtering. Proposal 2 adopts the p-q theory in with the Dual Second Order Generalized Integrator-Phase Locked Loop (DSOGI-PLL) algorithm to ensure correct harmonic compensation. Proposal 3 uses Conservative Power Theory (CPT) for selective compensation of reactive power, phase unbalances and active filtering in electrical power systems. Four case studies are carried out to evaluate how the connection of non-linear, unbalanced and reactive loads in the PAC affects the power quality of the voltages and currents in the electrical grid. Case 1 evaluates the system without active compensation, while cases 2, 3 and 4 investigate the behavior of the wind system with proposals 1, 2 and 3, in that order. Case 1 showed grid current Total Demand Distortion (TDD) values above those allowed by IEEE regulation 519 in all the intervals analyzed. Case 2 showed the lowest current TDD of all the cases, in line with the IEEE standard. Case 4 showed a grid voltage Total Harmonic Distortion (THD) lower than or equal to cases 2 and 3. In 12.5 s, the reactive power injected into the PAC was 0 VAr, 2540 VAr, 392 kVAr and 388 VAr, for cases 1, 2, 3 and 4, respectively. The standard deviation of the amplitudes of the phases of the mains currents were 16.57 A, 11.84 A, 10.17 A and 9.36 A at t= 12.5 s, for cases 1, 2, 3 and 4, in that order. Thus, proposals 1, 2 and 3 improve the power quality of the electrical system, as well as guaranteeing the delivery of power to the grid.