Um Estudo Comparativo de Controladores de Corrente Aplicados a Conversores Conectados à Rede Baseado em Hardware-in-the-loop

Abstract

This paper presents the execution of tests used for the comparison of three state feedback current controllers obtained from the linear quadratic regulator applied to grid- connected converters based on the control system implementation in Hardware-in-the-loop. The paper contribution is in the detailed description of three tests for the closed-loop control system validation, using a Hardware-in-the-loop to emulate the power portion of the converter, and a digital signal processor widely used in the literature for the real-time implementation of the digital control. The first test allows to conclude about the stability under variations in the grid impedance and also in real-time operation. The second test allows to conclude on the ability to tracking grid current references with phase and amplitude variations, providing a measure of the integral squared error. The third test allows to conclude on the ability to reject harmonics in the grid voltage in steady state, providing as a measure the total harmonic distortion of the grid currents and verifying the compliance of the harmonics with the limits of the IEEE 1547 Standard. The results consider grid voltage synchronization, implementation delay in the control signal, and the effect of vector modulation, presenting the grid-injected currents for each of the controllers in comparison, and the relevant metrics for the tests, indicating the feasibility of practical implementation of these controllers.