Procedimentos metodológicos de projeto do controlador multimalhas aplicado na malha de controle de tensão de um sistema PV de duplo estágio de conversão de energia

Abstract

This Bachelor's Dissertation deals with methodologic procedures of design of the multi-loop controller applied to the voltage control loop of a double-stage PV system. This double-stage connection is composed of a DC-DC Boost converter and a current-controlled voltage inverter. The study aims to develop a methodologic procedure for the project of multi-loop controllers. For this purpose, it is necessary to obtain the DC-DC Boost converter transfer functions, as well as to evaluate the advantages of employing the multi-loop controller instead of the single-loop PI controller, or even, to evaluate the advantages of replacing the proportional-integrative (PI) inner loop controller by a P controller of the PV array voltage control. Therefore, a small signal modelling technique is employed and, also, the frequency response analyses of transfer functions for the controller project. In the following, it will be defined the criteria to determine the multi-loop controller design specifications, such as phase margin and crossover frequency in 0 dB, ensuring stability and performance to the controlled system. Furthermore, through computer simulation and experimental results, the performance of these controllers projected following the established project criteria will be tested and compared to the performance of a multi-loop controller designed according to existing methodologies adopted in the literature. In addition, the comparison analysis will also include the performance of the single-loop PI controller. The main difficulties in designing the multi- loop controller are pointed out and discussed, highlighting the importance of this work's contribution.