Grid harmonic current correction based on two parallel three-phase DC-AC converters

• Autor(a) principal: Souza, Laysa Lúcia de
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFPB
• Texto Completo: https://repositorio.ufpb.br/jspui/handle/123456789/21077
• topic: Controle preditivo; Corrente de circulação; Função custo; FS-MPC; Inversores conectados em paralelo; Circulating current; Cost function; Model predictive control; Parallel inverters; CNPQ::ENGENHARIAS::ENGENHARIA ELETRICA

This work presents a finite set model predictive control (FS-MPC) applied to three-phase Shunt Active Power Filters (SAPF): the conventional SAPF and the SAPF with two parallel inverters sharing the sarne DC-link. The mathematical model of the SAPF is used to form the FS-MPC algorithm. The variables to be controlled are initially measured and, using the equations of the model in discrete time, the predictions of these variables for the next sampling step are determined. Each switching state vector is tested using the cost function, and the switching vector responsible for minimizing the cost function is chosen for application in the next sampling instant. ln the case of SAPF presented in this work, the variables to be controlled and analyzed are the grid, SAPF, circulation and offset currents. The circulation and offset currents are only present in SAPF with two inverters and occur due to the parallel connection between them. For the conventional SAPF, 8 switching state vectors are applied, while for SAPF with two inverters 64 are considered. After a vector selection process in which the switching states that are chosen are able to satisfy the criteria of adequate modulation of the SAPF voltage and mitigation of the circulation and offset currents, 30 vectors are chosen and these are applied to the SAPF with two parallel inverters. This selection is made based on the identification of redundant vectors and also in order to reduce the algorithm processing time. The control system aims to ensure sinusoidal grid current with a high power factor, free of harmonic components, in addition to minimizing the circulation and offset currents derived from the parallel inverters. ln addition, the effects caused by the variation of some parameters present in the control strategy and elements of the filter itself are also analyzed. To prove the efficiency of the FS-MPC applied in the SAPF with two parallel inverters, simulation and experimental results are presented for both topologies using FS-MPC and also considering the conventional SAPF using the PWM strategy.