A comparative study of central and distributed MPPT architectures for megawatt utility and large scale commercial photovoltaic plants

Elasser, Ahmed; Agamy, Mohammed; Sabate, Juan; Steigerwald, R.L.; Fisher, R. M.; Todorovic, Maja Harfman

doi:10.1109/iecon.2010.5675108

Cited by 75 publications

(24 citation statements)

References 9 publications

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“…The power conversion and grid integration for MW scale PV power plants become more complex as size of the installation increases [2]. It has become a great challenge to ensure their operation at high availability, reliability and efficiency.…”

Section: Introductionmentioning

confidence: 99%

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A new multilevel converter for Megawatt scale solar photovoltaic utility integration

Krishnamoorthy

Essakiappan

Enjeti

et al. 2012

2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

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This paper presents a new multi-level DC-AC-AC converter topology for medium voltage grid integration of Megawatt (MW) scale utility photovoltaic (PV) plants. It is envisioned that a large PV field is divided into many zones, each comprising of two PV arrays. The number of zones depends on the voltage of the grid with which it is interfaced. In the proposed approach, zonal power balancing is achieved by employing a current-sharing technique. The power conversion architecture consists of an IGBT based full-bridge inverter feeding a medium frequency (MF) transformer with three secondary windings. The voltages at the transformer secondaries are then converted to three phase line frequency AC by three, full-bridge AC-AC converters. This also eliminates the 2 nd harmonic power from the DC bus, thereby reducing the capacitor size. By stacking several such modules in series, a high quality multilevel medium voltage output is generated. Further, the bulky line frequency utility interface transformer is eliminated. A new control method is proposed for the series connected modules during partial shading while minimizing the switch ratings. This paper presents the analysis, design example and simulation of a 10 MW PV system with preliminary experimental results on a laboratory prototype.

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Section: Introductionmentioning

confidence: 99%

“…Many such systems are interfaced to the utility in parallel, as shown in fig. 1, based on the desired power rating of the plant [2] [3]. The system in fig.…”

Section: Introductionmentioning

confidence: 99%

A new multilevel converter for Megawatt scale solar photovoltaic utility integration

Krishnamoorthy

Essakiappan

Enjeti

et al. 2012

2012 Twenty-Seventh Annual IEEE Applied Power Electronics Conference and Exposition (APEC)

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“…Prior estimates of performance improvement from the use of distributed power electronics indicate that the potential for mismatch power recovery depends greatly on the site-specific details of the PV installation [4][5][6]. Additional potential benefits of distributed power electronics include increased design flexibility by allowing mismatched or longer strings of PV panels, improved monitoring, and increased system availability [7][8][9]. Despite these potential benefits, a critical factor in distributed power converters' utility is their conversion efficiency, which needs to be high in order to compete with conventional centralized inverter approaches [10].…”

Section: Introductionmentioning

confidence: 99%

Use conditions and efficiency measurements of DC power optimizers for photovoltaic systems

Deline

MacAlpine

2013

2013 IEEE Energy Conversion Congress and Exposition

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No consensus standard exists for estimating annual conversion efficiency of DC-DC converters or power optimizers in photovoltaic (PV) applications. The performance benefits of PV power electronics including per-panel DC-DC converters depend in large part on the operating conditions of the PV system, along with the performance characteristics of the power optimizer itself. This work presents a case study of three system configurations that take advantage of the capabilities of DC power optimizers. Measured conversion efficiencies of DC-DC converters are applied to these scenarios to determine the annual weighted operating efficiency. A simplified general method of reporting weighted efficiency is given, based on the California Energy Commission's CEC efficiency rating and several input / output voltage ratios. Efficiency measurements of commercial power optimizer products are presented using the new performance metric, along with a description of the limitations of the approach.

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“…When sun exposure of the modules is uniform, a single (centralized) inverter can be used in small-medium PV plant. In other cases, when non uniform working conditions are more likely, string inverters or micro inverters are used instead [2][3][4]. Moreover performances of an unequally irradiated PV plant can be improved by different connection topologies of the PV plant.…”

Section: Introductionmentioning

confidence: 99%

Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays

et al. 2015

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Abstract:In order to reduce the mismatch effect caused by non-uniform shadows in PV arrays, reconfigurable interconnections approaches have been recently proposed in the literature. These systems usually require the knowledge of the solar radiation affecting every solar module. The aim of this work is to evaluate the effectiveness of three irradiance estimation approaches in order to define which can be well suited for reconfigurable PV arrays. It is presented a real-time solar irradiance estimation device (IrradEst), implementing the three different estimation methods. The proposed system is based on mathematical models of PV modules enabling to estimate irradiation values by sensing a combination of temperature, voltage and current of a PV module. Experimental results showed generally good agreement between the estimated irradiances and the measurements performed by a standard pyranometer taken as reference. Finally one of the three methods was selected as possible solution for a reconfigurable PV system.

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A comparative study of central and distributed MPPT architectures for megawatt utility and large scale commercial photovoltaic plants

Cited by 75 publications

References 9 publications

A new multilevel converter for Megawatt scale solar photovoltaic utility integration

A new multilevel converter for Megawatt scale solar photovoltaic utility integration

Use conditions and efficiency measurements of DC power optimizers for photovoltaic systems

Proof of Concept of an Irradiance Estimation System for Reconfigurable Photovoltaic Arrays

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