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The idea of combining both thermal and photovoltaic collectors in hybrid photovoltaic-thermal (PV-T) modules actually shows a great potential for integration on facades and rooftops of buildings, mainly because of the reduced available space and the benefits of the on-site electricity and thermal generation. The objective of this work is to compare the real performance (experimental data obtained under real sun during a year) of a commercial hybrid PV-T system vs. a simple PV system using microinverters, assessing the suitability of one-unit hybrid PV-T systems vs. two separated units – PV systems + Thermal systems – for building integration. The combined efficiency over the span of a full day could reach values up to 80%, but this apparent high value needs to be analysed in detail. From the experimental results, it can be observed that both systems, PV and PV-T, have a good electrical performance. But the PV-T system output does not benefit from the lower module temperatures that it should achieve from the active cooling in its back, presenting the same performance as the simple PV system. Regarding the microinverters configuration performance, it has been very positive working with high efficiencies above 96%, justifying its use in this type of applications. In conclusion, the commercial PV-T system has not performed as expected, showing problems with the integration of the active cooling in the back of the PV modules. At this moment, and despite the potential of PV-T systems for BIPV due to space limitations, commercial PV-T systems are still far from PV and Thermal systems using separately. [ABSTRACT FROM AUTHOR]

Building Integrated and Building Attached Photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of not considered partial shading. New system architectures have been proposed to optimize performance. The common approach of these new architectures is to track the Maximum Power Point (MPP) of every solar module individually. A simulation model is developed to quantify the benefits and drawbacks of different PV system architectures. The model includes a shading evaluation of the installation with means of 3D modeling, irradiance calculations, PV cell modeling and finally an empirical power conversion model. The energy yield of three leading architectures is confirmed (string inverter, power optimizer, micro inverter) for clear and partial shading conditions by means of an outdoor field test. Results with the irradiance profile of the Netherlands show that the string inverter system outperforms MLPE in 2 out of 3 partial shading scenarios that were evaluated in this study. It is found that the energy yield benefit of MLPE has a seasonal and latitude variation with the highest contribution during winter months. Additionally a study was performed to evaluate the energy yield at different irradiance profiles. Results show that there is a marginal benefit of the micro inverter system at higher irradiance locations when partial shading is present. The analysis method can be used by PV installers and system designer to determine which is the optimal system architecture for maximum energy yield especially when partial shading is present. [ABSTRACT FROM AUTHOR]

Building integrated and building attached photovoltaic (BIPV, BAPV) systems may suffer from lower performance than predicted as a result of unwanted partial shading. New system architectures have been proposed to optimize performance. The common approach of these new architectures is to track the maximum power point of every solar module individually. This paper demonstrates the effect of shading on energy yield by evaluating power level management on the module level compared to string level. Three independent PV systems were installed and extensively monitored in Eindhoven, a reference string inverter system, a power optimizer system and a micro inverter system. The DC and AC performance ratio (PR) of the systems have been analyzed for different weather types based on the clearness index. A pole shading covering 1-2% of the total system surface has been used to evaluate system performance under a specific type of partial shading. Module Level Power Electronics (MLPE) is capable of increasing the PR up to 35% under certain partial shading conditions. However, the string inverter system outperformed MLPE under unshaded operation conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT The use of modular or 'micro' maximum power point tracking (MPPT) converters at module level in series association, commercially known as 'power optimizers', allows the individual adaptation of each panel to the load, solving part of the problems related to partial shadows and different tilt and/or orientation angles of the photovoltaic (PV) modules. This is particularly relevant in building integrated PV systems. This paper presents useful behavioural analytical studies of cascade MPPT converters and evaluation test results of a prototype developed under a Spanish national research project. On the one hand, this work focuses on the development of new useful expressions which can be used to identify the behaviour of individual MPPT converters applied to each module and connected in series, in a typical grid-connected PV system. On the other hand, a novel characterization method of MPPT converters is developed, and experimental results of the prototype are obtained: when individual partial shading is applied, and they are connected in a typical grid connected PV array. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Building integrated photovoltaic (BIPV) systems bring forward many requirements to grid-tied inverters in these aspects such as generating efficiency, shading effects, harmonic & reactive current compensation and quick economical payback, etc.. This paper presents a multi-functional utility interface of BIPV systems based on cascade multilevel converter. It has two operating modes: one is operated as grid-tied inverter at normal insolation level and the other is operated as active power filter (APF) at very low insolation level or at nighttime. Compared with traditional inverters, cascade multilevel converter is much more efficient and suitable for utility interface of BIPV system because it has the merits of high efficiency, minimum switching frequency, low switching stress and EMI, approximate sinusoidal waveform voltage output with low total harmonic distortion (THD), modular structure and good dynamic stability. Simulation and experimental results have verified its feasibility and advantage. [Copyright &y& Elsevier]

This paper presents the designed proposal of a solar PV and grid-connected electricity system with multiple modes operation for homes and buildings. It introduces to a more resourceful solar PV system that suits with the needs for different occasions rather have to be limited to one particular application. This concept uses a DC motor and synchronous generator as an electromechanical inverter to alternatively present popular approach of using solid-state inverters in converting the solar DC supply into AC, suitable to run common electrical appliances. The block concept of the system and the main controller with programming flowcharts for the multiple operations are proposed for a 2kW output power. [ABSTRACT FROM AUTHOR]

Since building-integrated photovoltaic (BIPV) modules are typically installed during, not after, the construction phase, BIPVs have a profound impact compared to conventional building-applied photovoltaics on the electrical installation and construction planning of a building. As the cost of BIPV modules decreases over time, the impact of electrical system architecture and converters will become more prevalent in the overall cost of the system. This manuscript provides an overview of potential BIPV electrical architectures. System-level criteria for BIPV installations are established, thus providing a reference framework to compare electrical architectures. To achieve modularity and to minimize engineering costs, module-level DC/DC converters preinstalled in the BIPV module turned out to be the best solution. The second part of this paper establishes converter-level requirements, derived and related to the BIPV system. These include measures to increase the converter fault tolerance for extended availability and to ensure essential safety features. [ABSTRACT FROM AUTHOR]

Photovoltaic electricity generation is growing at an almost exponential rate worldwide, reaching 400 GWp of installed capacity in 2018. Different types of installations, ranging from small building integrated systems to large plants, require different maintenance strategies, including strategies for monitorization and data processing. In this article, we present three case studies at different scales (from hundreds of Wp to a 2.1 MWp plant), where automated parameter monitorization and data analysis has been carried out, aiming to detect failures and provide recommendations for optimum maintenance procedures. For larger systems, the data collected by the inverters provides the best source of information, and the cross-correlated analysis which uses these data is the best strategy to detect failures in module strings and failures in the inverters themselves (an average of 32.2% of inverters with failures was found after ten years of operation). In regards to determining which module is failing, the analysis of thermographic images is reliable and allows the detection of the failed module within the string (up to 1.5% for grave failures and 9.1% of medium failures for the solar plant after eleven years of activity). Photovoltaic (PV) systems at different scales require different methods for monitorization: Medium and large systems depend on inverter automated data acquisition, which can be complemented with thermographic images. Nevertheless, if the purpose of the monitorization is to obtain detailed information about the degradation processes of the solar cells, it becomes necessary to measure the environmental (irradiance and ambient temperature), thermal and electrical parameters (I-V characterization) of the modules and compare the experimental data with the modelling results. This is only achievable in small systems. [ABSTRACT FROM AUTHOR]