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This paper presents an innovative solution for the enhancement of the single-stage photovoltaic systems grid-tied topology. The proposed approach involves the integration of an Active Power Filter (APF) with a Quasi-Z-Source Inverter (qZSI) that are controlled by a modified Synchronous Reference Frame (SRF) approach. Indeed, the conventional grid-tied PV systems often face challenges such as grid instability, harmonic distortion, and power quality issues. These issues can lead to inefficient energy transfer and potential damage to grid equipment. In response to these challenges, the proposed system integrates an APF with a qZSI that allows offering advanced grid-support features including harmonics mitigation, reactive power compensation, and voltage regulation. The proposed topology based on qZSI-APF can actively manage the power flow and ensure grid stability of operation mode of the single-stage photovoltaic systems grid-tied even under varying operating conditions. Furthermore, the applied control strategy, based on a modified SRF approach, enables precise current control and seamless interaction with the grid. Hence, the combination of the proposed topology with the applied control technique allows ensuring efficient utilization of renewable energy resources while maintaining the grid reliability and stability. For the validation of the proposed topology, simulations based on Matlab/Simulink environment have been carried out to prove the effectiveness of the proposed topology. The obtained results demonstrate improved grid integration performance, reduced harmonic distortion, enhanced power quality, and better voltage regulation. It can be said that the proposed topology offers a promising solution for addressing the challenges associated with grid integration of PV systems, paving the way for overcoming the main faced problems related to the increased renewable energy deployment and hence ensuring sustainable and clean energy sources. [ABSTRACT FROM AUTHOR]

This paper proposes a new multifunctional control technique for a grid-connected hybrid distributed generation system composed of a photovoltaic system and a wind power system based on a voltage source converter (VSC). Indeed, aside from the generation and the injection of energy into the grid, the proposed system deals with power quality issues caused by harmonics generated by non-linear loads in order to keep the source current uncontaminated. The VSC serves to first ensure that the power generated from the hybrid renewable energy source is fed to the utility grid and acts as a shunt active power filter in case an abnormal increase in the THD of the source current above the standard permissible values is detected due to the non-linear load connection. The two sources of the hybrid system are connected to a common DC bus to simplify the control and reduce the cost of the system, and a maximum power point tracking controller is used for both sources. The major advantage of this novel proposed multifunctional control technique is its ability to inject harvested power into the grid while simultaneously ensuring the compensation of the harmonics and reactive power. The proposed multifunctional control technique is validated through an extensive simulation analysis using MATLAB/Simulink. [ABSTRACT FROM AUTHOR]

Due to the growing demand for photovoltaic power generation systems for grid-connected renewable energy systems, the high-quality energy and the good efficiency are necessary. For this reason, two-level parallel inverters are used in grid-connected PV systems connected to standard AC and DC connections are widely utilized. This structure is often relied on to raise the quality of the power and increase the power conversion efficiency. This article proposes a grid-tied energetic system composed of a photovoltaic source connected to the grid by the means of DC-DC boost converter controlled by hell clamping algorithm MPPT to improve the harvesting of the PV power, and of two VSIs connected in parallel interfaced by a coupling filter and controlled by two methods namely, classic DPC-PI and improved DPC-ST. An extensive simulation analysis was carried out to validate the proposed control approach by the comparison with the conventional method base on PI regulator. The proposed technique introduced a superior performance in terms of lower voltage stress at the DC-link, the THD of the injected current, and the ripples of the active and reactive power. [ABSTRACT FROM AUTHOR]

Multi-level inverters have become widely used in several high and medium power applications owing to their improved output voltage compared with the output voltage provided by two level inverters. However, when a fault occurs in a cell in the converter it could lead to a failure or malfunction on the application chain of the whole system. Therefore, automatic failure detection is becoming more and more essential. In this paper, a new algorithm is developed for switch open-circuit fault detection and localisation in a flying capacitor multilevel converter. The proposed algorithm is not dedicated only for the fault detection, but also for faulty switch localization. Since the output voltage of the FC converter is totally related to the control applied on the switches, the proposed technique requires only the output voltage and pulse width modulation (PWM) switching signals. A mathematical model is developed to provide a reference signal for all the considered faulty cases. Next, the faulty switch is precisely located after performing a procedure through several comparators and filters. This paper aims first to provide detailed explanation of the proposed algorithm, followed by a validation through an extensive simulation and finally the analysis of the results, which confirm the performance of the proposed technique. [ABSTRACT FROM AUTHOR]