Implementação de algoritmos de otimização heurísticos no rastreamento do ponto de máxima potência em um sistema de geração distribuída eólico conectado à rede elétrica trifásica

Abstract

This paper presents the implementation of Maximum Power Point Tracking (MPPT) algorithms applied to Wind Energy Conversion System (WECS) with full power conversion connected to the three-phase utility grid. Full power conversion topologies represented a major advance to the wind power systems, because the rotation speed variation of the generator connected to the wind turbine is allowed, being possible to apply optimization techniques in the search of MPP. Two converters with back-to-back connection are used for the power conversion. The MPPT algorithms are applied in the rectification power stage based on information provided by the wind turbine. Thus, since the wind turbine output electric power must be controlled for applying the optimization algorithms, a controlled rectifier is used. A three-phase inverter is used as interface between the rectifier and the grid, being its output currents controlled. Some heuristic MPPT techniques are applied to improve the wind system performance, such as P&O (Perturb and Observe) and IC (Incremental Conductance). In order to evaluate the ability to search the MPP, such techniques are subjected to abrupt oscillations of the wind speed. This work also presents the mathematical modeling of the controlled rectifier, the inverter into the dy synchronous reference frame, and the DC bus. Computational simulations results are shown in order to evaluate the wind system performance.