A repetitive predictive control for grid-connected inverter current control scheme is presented in this paper under voltage harmonic distortion in the stationary reference frame. Predictive control is an approach that uses a receding horizon to achieve the optimal track for the reference. In this approach, the repetitive controller behavior is added to the predictive control to increase its performance under distorted voltage conditions. In addition, to apply the controller in the generation system, controller is designed from the perspectives of the power system. The controller is designed considering the state-space model in the stationary reference frame. The controller performance was verified using a laboratory experimental setup under distorted grid voltage condition. Experimental results confirm that the proposed controller can effectively suppress harmonics under both normal operation and distorted grid voltage conditions, and also satisfy the requirements stipulated in IEEE Std. 1547.2-2008.

This research paper presents a model of predictive control with a modulator for the inverter linked to the electrical grid, using the stationary reference frame and operating under grid distorted voltage. The stationary reference frame model for the system is obtained in its fundamental frequency and then the model predictive technique is implemented, which predicts the system actions using the obtained system model without the need of any other harmonic consideration. The controller calculates the voltage vector of the inverter through the minimization of the cost function. Thus, the proposal demonstrates, through experiments, its positive results regarding the low impact of the distorted voltage in the grid current without using any harmonic consideration on the model. Experimental results and comparisons carried out endorse the proposal of this work.

This work introduces a new method for computing the angular position of the voltage of the grid—based on a finite set of angles—in the condition of failures in the distribution systems, as symmetrical and asymmetric voltage sags, unbalance, harmonic distortions, and frequency changes. This method is inspired in the model predictive control finite control set principles. In this way, the proposal employs the One-Cycle Fourier filter (OCF) to estimate the positive sequence of the voltage vector into the stationary $\alpha \beta$-frame. The positive sequence voltages extracted from this filter is then handled by an algorithm that is implemented by a finite position set (FPS) for estimating the phase angle. In this way, the minimized cost function chooses the optimal angular position while using the predicted behavior of the grid voltage vector elements in $dq$ frame. The structure, called One-Cycle Fourier Finite position Set Phase Locked Loop (OCF-FS-PLL), here is a composition of the OCF and the FPS. The results that were obtained in an experimental test bench validate the proposed method.

In this work, it is proposed an amendment in one of the operation modes of a nine switch inverter (NSI) which is used to interface a photovoltaic system and a series compensator for voltage sag mitigation. The NSI Fault Operation mode is commonly applied to correct balanced three-phase faults, whose occurrence is less than 10% of the overall faults affecting power grids. In the proposed NSI, a fourth wire allows the correction of asymmetric faults, which increases its performance and consequently makes the system more attractive. Furthermore, the modulation technique used in this mode must address the asymmetric corrections without interfering with the others NSI functionalities. Simulated results are presented and show that the method is promising. Experimental results corroborate this proposal.

Neste trabalho, apresenta-se uma estratégia de controle aplicada a um sistema para inserção de energia fotovoltaica na rede e compensação de tensão na carga. Como parte da estratégia de controle, faz-se uso de uma técnica que utiliza separadamente as componentes de sequência positiva, negativa e zero da tensão no Ponto de Acoplamento Comum (PAC), aqui denominada Decomposição Instantânea em Componentes de Sequência (DICSE). A metodologia proposta provê ao sistema a capacidade de operar adequadamente mesmo durante a ocorrência de faltas assimétricas no PAC. Para validar esta contribuição foram realizadas simulações em tempo real, onde o sistema foi submetido a dois diferentes tipos de faltas assimétricas. As faltas consideradas são do tipo curto-circuito. A partir dos resultados obtidos conclui-se que o método proposto é promissor, pois agrega mais robustez ao sistema, tendo em vista que a maioria das faltas ocorridas nos sistemas de distribuição são do tipo assimétricas.