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The transformerless inverters are widely employed in grid-tied PV systems, since they feature higher efficiency and lower cost compared with the transformer based inverters. One of the critical problems for transformerless inverters is the common-mode leakage current issue, which leads to serious safety and EMI problems. This paper proposed an enhanced HERIC based single-phase transformerless inverter...
Photovoltaic power plants (PV) are equipped with anti-islanding algorithms, embedded in the converters controller, to avoid the island operation. However, the current trends in the development of the future electrical networks evidence that it is technically feasible and economically advantageous to keep feeding islanded systems under these situations, without cutting the power supply to the loads...
Leakage current reduction is one of the most important issues for transformerless PV grid-connected inverters. Many interesting single-phase topologies have been reported to reduce the leakage currents. However, three-phase PV inverter topologies with reduced leakage currents are not received much attention. In this paper, a new family of three-phase topology is proposed to reduce the leakage current...
This paper presents a modular multilevel cascade converter (MMCC) based on chopper-cells for a grid-connected photovoltaic (PV) application suitable to medium and high voltage systems without line-frequency transformers. This converter is characterized by a modular arm structure composed by cascaded chopper-cells with floating dc capacitors, each one connected to a photovoltaic panel. This paper proposes...
Low cost digital-analog hybrid control for photovoltaic battery charger is studied in this paper. An interleaved boost circuit is used as the power converter. The interleaving control for the interleaved boost is realized with an analog IC. The change-discharge strategy for battery and an improved maximum power point tracking (MPPT) algorithm are realized with a low performance digital control chip...
A battery energy storage system (BESS) for a utility scale photovoltaic (PV) power plant is proposed. PV systems suffer from intermittency and partial shading problems, which could lead to power fluctuations and reduce grid stability. Utilities' inability to service the contracted load might lead to hefty penalties by the regulators. To reduce the effects of intermittency on PV output, a utility scale...
Energy storage systems integration with large-scale PV power plants, named Intelligent PV power plant (IPV), could contribute to improve the viability of these plants and to provide ancillary services to the main grid. The number and extension of the provided services depend not only on the size of the storage system, but also on the manner how this storage system is managed. In this paper the market...
Static partial shading on large photovoltaic arrays has already been modeled by many researchers over the last two decades. However, little research has been devoted to dynamic partial shading that is more realistic in practice. This project investigates an efficient MATLAB-based model that incorporates the dynamic characteristics of a photovoltaic (PV) module under a non-ideal moving shadow which...
Photovoltaic systems require the implementation of maximum power point tracking (MPPT) algorithms to maximize power extracted from these systems. However, the application of such algorithms in grid-connected droop-controlled systems is hampered by differences in the dynamic responses of the respective techniques. In this context, this study presents the development of a strategy that enables a push-pull...
Various photovoltaic PV models of different complexity exist in the literature. The modeling accuracy for most of them is directly related to their complexity and computational effort. Recently, two newly developed PV models featuring low computational effort and high accuracy appeared in the literature. The first model is developed based on Gompertz model which is originally used to model human mortality,...
A transformer-less grid-connected inverter is presented for photovoltaic generation system. The proposed inverter topology features low leakage current and no need for split capacitors. The topology, basic operating principles and pulse-width modulation scheme for the proposed inverter are described. Moreover the characteristic of leakage current of the proposed topology is analyzed. Experimental...
Electrical mismatch between modules in a PV array due to partial shading causes energy losses beyond the shaded module. This occurs because unshaded modules are forced to operate away from their maximum power point in order to compensate for the shading. Here we present an irradiance estimation algorithm for use in a mismatch mitigation system. Irradiance is estimated using measurements of module...
This paper presents a model for calculating the optimal size of a grid connected DC micro-grid. Considering the differences between DC micro-grid and general AC micro-grid and the operating mode of the DC micro-grid system with hybrid energy storage system, the sum of the total capital, operational and maintenance cost of distributed generations (DGs) are set as the optimal objective. A numerical...
This paper presents a three-port soft switching dc-dc converter topology based on the bidirectional version of the three-state switching cell (3SSC) and dual active bridge (DAB), feasible to interconnect battery banks with a dc link and photovoltaic panels. The converter features high voltage gain and current reduced stress in the converter primary switches. All active switches are designed to operate...
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