Operação coordenada e otimizada de condicionadores unificados de qualidade de energia trifásicos conectados em paralelo

Abstract

The present thesis proposes the study of three-phase Unified Power Quality Conditioners (UPQC) operating in a coordinated and parallel manner, with two distinct topologies analyzed, working in dual/inverted active power compensation mode: i) a UPQC composed of a Three-Leg (3L) series voltage source inverter (VSI) and a Four-Leg (4L) parallel VSI, and ii) a UPQC composed of series and parallel NPC (Neutral Point Clamped) VSIs. In this context, was systematically developed throughout the work a linearized small-signal statespace model, considering a network composed of the aforementioned UPQCs operating in parallel, based on the droop control strategy, distribution lines and loads. In order to improve the control performance of UPQCs in parallel operation, this work also considers the application of the Differential Evolution (DE) metaheuristic to obtain an optimized adjustment of the parameters of the controllers involved in the system, particularly in the voltage and current control loops of the UPQCs, whose optimization process is related to the minimization of cost functions interrelated with the dynamic behavior of the system. Computational simulations are presented and evaluated considering general operating contexts, in which control strategies for the restoration of the frequency and voltage variables of the system are employed, in this case, secondary control loops and washout filters, being applied in conjunction with the droop control. Analyses of the active and reactive power flows are also performed for these simulations aiming at a better understanding of the parallel operation of the UPQCs. In addition, temporal responses were obtained for the linearized small-signal model developed and also illustrated aiming at its computational validation. Experimental tests were conducted considering the operation of only parallel VSIs of two UPQC prototypes, which were adapted to operate with 3L topologies, applied to three-wire systems, with the results of the parallelism of these converters being presented throughout the work.